diff --git a/README.md b/README.md
index 3a29eb0..cf3e589 100644
--- a/README.md
+++ b/README.md
@@ -25,32 +25,37 @@ The latest prototype is in the folder `app-proto`. It includes both a user inter
 ### Install the prerequisites
 
 1. Install [`rustup`](https://rust-lang.github.io/rustup/): the officially recommended Rust toolchain manager
-   * It's available on Ubuntu as a [Snap](https://snapcraft.io/rustup)
+   - It's available on Ubuntu as a [Snap](https://snapcraft.io/rustup)
 2. Call `rustup default stable` to "download the latest stable release of Rust and set it as your default toolchain"
-   * If you forget, the `rustup` [help system](https://github.com/rust-lang/rustup/blob/d9b3601c3feb2e88cf3f8ca4f7ab4fdad71441fd/src/errors.rs#L109-L112) will remind you
+   - If you forget, the `rustup` [help system](https://github.com/rust-lang/rustup/blob/d9b3601c3feb2e88cf3f8ca4f7ab4fdad71441fd/src/errors.rs#L109-L112) will remind you
 3. Call `rustup target add wasm32-unknown-unknown` to add the [most generic 32-bit WebAssembly target](https://doc.rust-lang.org/nightly/rustc/platform-support/wasm32-unknown-unknown.html)
 4. Call `cargo install wasm-pack` to install the [WebAssembly toolchain](https://rustwasm.github.io/docs/wasm-pack/)
 5. Call `cargo install trunk` to install the [Trunk](https://trunkrs.dev/) web-build tool
 6. Add the `.cargo/bin` folder in your home directory to your executable search path
-   * This lets you call Trunk, and other tools installed by Cargo, without specifying their paths
-   * On POSIX systems, the search path is stored in the `PATH` environment variable
+   - This lets you call Trunk, and other tools installed by Cargo, without specifying their paths
+   - On POSIX systems, the search path is stored in the `PATH` environment variable
 
 ### Play with the prototype
 
 1. From the `app-proto` folder, call `trunk serve --release` to build and serve the prototype
-   * *The crates the prototype depends on will be downloaded and served automatically*
-   * *For a faster build, at the expense of a much slower prototype, you can call `trunk serve` without the `--release` flag*
-   * *If you want to stay in the top-level folder, you can call `trunk serve --config app-proto [--release]`* from there instead.
+   - The crates the prototype depends on will be downloaded and served automatically
+   - For a faster build, at the expense of a much slower prototype, you can call `trunk serve` without the `--release` flag
+   - If you want to stay in the top-level folder, you can call `trunk serve --config app-proto [--release]` from there instead.
 3. In a web browser, visit one of the URLs listed under the message `INFO 📡 server listening at:`
-   * *Touching any file in the `app-proto` folder will make Trunk rebuild and live-reload the prototype*
+   - Touching any file in the `app-proto` folder will make Trunk rebuild and live-reload the prototype
 4. Press *ctrl+C* in the shell where Trunk is running to stop serving the prototype
 
 ### Run the engine on some example problems
 
-1. Go into the `app-proto` folder
-2. Call `./run-examples`
-   * *For each example problem, the engine will print the value of the loss function at each optimization step*
-   * *The first example that prints is the same as the Irisawa hexlet example from the Julia version of the engine prototype. If you go into `engine-proto/gram-test`, launch Julia, and then*
+1. Use `sh` to run the script `tools/run-examples.sh`
+   - The script is location-independent, so you can do this from anywhere in the dyna3 repository
+   - The call from the top level of the repository is:
+     
+     ```bash
+     sh tools/run-examples.sh
+     ```
+   - For each example problem, the engine will print the value of the loss function at each optimization step
+   - The first example that prints is the same as the Irisawa hexlet example from the Julia version of the engine prototype. If you go into `engine-proto/gram-test`, launch Julia, and then
      
      ```julia
      include("irisawa-hexlet.jl")
@@ -59,9 +64,24 @@ The latest prototype is in the folder `app-proto`. It includes both a user inter
      end
      ```
      
-     *you should see that it prints basically the same loss history until the last few steps, when the lower default precision of the Rust engine really starts to show*
+     you should see that it prints basically the same loss history until the last few steps, when the lower default precision of the Rust engine really starts to show
 
 ### Run the automated tests
 
 1. Go into the `app-proto` folder
 2. Call `cargo test`
+
+### Deploy the prototype
+
+1. From the `app-proto` folder, call `trunk build --release`
+   - Building in [release mode](https://doc.rust-lang.org/cargo/reference/profiles.html#release) produces an executable which is smaller and often much faster, but harder to debug and more time-consuming to build
+   - If you want to stay in the top-level folder, you can call `trunk build --config app-proto --release` from there instead
+2. Use `sh` to run the packaging script `tools/package-for-deployment.sh`.
+   - The script is location-independent, so you can do this from anywhere in the dyna3 repository
+   - The call from the top level of the repository is:
+     ```bash
+     sh tools/package-for-deployment.sh
+     ```
+   - This will overwrite or replace the files in `deploy/dyna3`
+3. Put the contents of `deploy/dyna3` in the folder on your server that the prototype will be served from.
+   - To simplify uploading, you might want to combine these files into an archive called `deploy/dyna3.zip`. Git has been set to ignore this path
\ No newline at end of file
diff --git a/app-proto/Trunk.toml b/app-proto/Trunk.toml
new file mode 100644
index 0000000..017deba
--- /dev/null
+++ b/app-proto/Trunk.toml
@@ -0,0 +1,2 @@
+[build]
+public_url = "./"
\ No newline at end of file
diff --git a/app-proto/examples/kaleidocycle.rs b/app-proto/examples/kaleidocycle.rs
index 7ca1f97..ae4eb07 100644
--- a/app-proto/examples/kaleidocycle.rs
+++ b/app-proto/examples/kaleidocycle.rs
@@ -23,7 +23,7 @@ fn main() {
         let twist_motion: DMatrix<_> = (0..N_POINTS).step_by(4).flat_map(
             |n| [
                 tangent.proj(&up.as_view(), n),
-                tangent.proj(&down.as_view(), n+1)
+                tangent.proj(&down.as_view(), n+1),
             ]
         ).sum();
         let normalization = 5.0 / twist_motion[(2, 0)];
diff --git a/app-proto/examples/point-on-sphere.rs b/app-proto/examples/point-on-sphere.rs
index 89dee76..a73490e 100644
--- a/app-proto/examples/point-on-sphere.rs
+++ b/app-proto/examples/point-on-sphere.rs
@@ -6,7 +6,7 @@ use dyna3::engine::{
     realize_gram,
     sphere,
     ConfigNeighborhood,
-    ConstraintProblem
+    ConstraintProblem,
 };
 
 fn main() {
@@ -25,7 +25,7 @@ fn main() {
     );
     print::title("Point on a sphere");
     print::realization_diagnostics(&realization);
-    if let Ok(ConfigNeighborhood{ config, .. }) = realization.result {
+    if let Ok(ConfigNeighborhood { config, .. }) = realization.result {
         print::gram_matrix(&config);
         print::config(&config);
     }
diff --git a/app-proto/examples/three-spheres.rs b/app-proto/examples/three-spheres.rs
index aa5a105..7901e31 100644
--- a/app-proto/examples/three-spheres.rs
+++ b/app-proto/examples/three-spheres.rs
@@ -5,7 +5,7 @@ use dyna3::engine::{
     realize_gram,
     sphere,
     ConfigNeighborhood,
-    ConstraintProblem
+    ConstraintProblem,
 };
 
 fn main() {
@@ -14,7 +14,7 @@ fn main() {
         &[
             sphere(1.0, 0.0, 0.0, 1.0),
             sphere(-0.5, a, 0.0, 1.0),
-            sphere(-0.5, -a, 0.0, 1.0)
+            sphere(-0.5, -a, 0.0, 1.0),
         ]
     });
     for j in 0..3 {
@@ -27,7 +27,7 @@ fn main() {
     );
     print::title("Three spheres");
     print::realization_diagnostics(&realization);
-    if let Ok(ConfigNeighborhood{ config, .. }) = realization.result {
+    if let Ok(ConfigNeighborhood { config, .. }) = realization.result {
         print::gram_matrix(&config);
     }
     print::loss_history(&realization.history);
diff --git a/app-proto/src/add_remove.rs b/app-proto/src/add_remove.rs
deleted file mode 100644
index d737c79..0000000
--- a/app-proto/src/add_remove.rs
+++ /dev/null
@@ -1,259 +0,0 @@
-use std::{f64::consts::FRAC_1_SQRT_2, rc::Rc};
-use sycamore::prelude::*;
-use web_sys::{console, wasm_bindgen::JsValue};
-
-use crate::{
-    AppState,
-    engine,
-    engine::DescentHistory,
-    assembly::{Assembly, InversiveDistanceRegulator, Point, Sphere}
-};
-
-/* DEBUG */
-// load an example assembly for testing. this code will be removed once we've
-// built a more formal test assembly system
-fn load_gen_assemb(assembly: &Assembly) {
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            String::from("gemini_a"),
-            String::from("Castor"),
-            [1.00_f32, 0.25_f32, 0.00_f32],
-            engine::sphere(0.5, 0.5, 0.0, 1.0)
-        )
-    );
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            String::from("gemini_b"),
-            String::from("Pollux"),
-            [0.00_f32, 0.25_f32, 1.00_f32],
-            engine::sphere(-0.5, -0.5, 0.0, 1.0)
-        )
-    );
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            String::from("ursa_major"),
-            String::from("Ursa major"),
-            [0.25_f32, 0.00_f32, 1.00_f32],
-            engine::sphere(-0.5, 0.5, 0.0, 0.75)
-        )
-    );
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            String::from("ursa_minor"),
-            String::from("Ursa minor"),
-            [0.25_f32, 1.00_f32, 0.00_f32],
-            engine::sphere(0.5, -0.5, 0.0, 0.5)
-        )
-    );
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            String::from("moon_deimos"),
-            String::from("Deimos"),
-            [0.75_f32, 0.75_f32, 0.00_f32],
-            engine::sphere(0.0, 0.15, 1.0, 0.25)
-        )
-    );
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            String::from("moon_phobos"),
-            String::from("Phobos"),
-            [0.00_f32, 0.75_f32, 0.50_f32],
-            engine::sphere(0.0, -0.15, -1.0, 0.25)
-        )
-    );
-}
-
-/* DEBUG */
-// load an example assembly for testing. this code will be removed once we've
-// built a more formal test assembly system
-fn load_low_curv_assemb(assembly: &Assembly) {
-    let a = 0.75_f64.sqrt();
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            "central".to_string(),
-            "Central".to_string(),
-            [0.75_f32, 0.75_f32, 0.75_f32],
-            engine::sphere(0.0, 0.0, 0.0, 1.0)
-        )
-    );
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            "assemb_plane".to_string(),
-            "Assembly plane".to_string(),
-            [0.75_f32, 0.75_f32, 0.75_f32],
-            engine::sphere_with_offset(0.0, 0.0, 1.0, 0.0, 0.0)
-        )
-    );
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            "side1".to_string(),
-            "Side 1".to_string(),
-            [1.00_f32, 0.00_f32, 0.25_f32],
-            engine::sphere_with_offset(1.0, 0.0, 0.0, 1.0, 0.0)
-        )
-    );
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            "side2".to_string(),
-            "Side 2".to_string(),
-            [0.25_f32, 1.00_f32, 0.00_f32],
-            engine::sphere_with_offset(-0.5, a, 0.0, 1.0, 0.0)
-        )
-    );
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            "side3".to_string(),
-            "Side 3".to_string(),
-            [0.00_f32, 0.25_f32, 1.00_f32],
-            engine::sphere_with_offset(-0.5, -a, 0.0, 1.0, 0.0)
-        )
-    );
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            "corner1".to_string(),
-            "Corner 1".to_string(),
-            [0.75_f32, 0.75_f32, 0.75_f32],
-            engine::sphere(-4.0/3.0, 0.0, 0.0, 1.0/3.0)
-        )
-    );
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            "corner2".to_string(),
-            "Corner 2".to_string(),
-            [0.75_f32, 0.75_f32, 0.75_f32],
-            engine::sphere(2.0/3.0, -4.0/3.0 * a, 0.0, 1.0/3.0)
-        )
-    );
-    let _ = assembly.try_insert_element(
-        Sphere::new(
-            String::from("corner3"),
-            String::from("Corner 3"),
-            [0.75_f32, 0.75_f32, 0.75_f32],
-            engine::sphere(2.0/3.0, 4.0/3.0 * a, 0.0, 1.0/3.0)
-        )
-    );
-}
-
-fn load_pointed_assemb(assembly: &Assembly) {
-    let _ = assembly.try_insert_element(
-        Point::new(
-            format!("point_front"),
-            format!("Front point"),
-            [0.75_f32, 0.75_f32, 0.75_f32],
-            engine::point(0.0, 0.0, FRAC_1_SQRT_2)
-        )
-    );
-    let _ = assembly.try_insert_element(
-        Point::new(
-            format!("point_back"),
-            format!("Back point"),
-            [0.75_f32, 0.75_f32, 0.75_f32],
-            engine::point(0.0, 0.0, -FRAC_1_SQRT_2)
-        )
-    );
-    for index_x in 0..=1 {
-        for index_y in 0..=1 {
-            let x = index_x as f64 - 0.5;
-            let y = index_y as f64 - 0.5;
-            
-            let _ = assembly.try_insert_element(
-                Sphere::new(
-                    format!("sphere{index_x}{index_y}"),
-                    format!("Sphere {index_x}{index_y}"),
-                    [0.5*(1.0 + x) as f32, 0.5*(1.0 + y) as f32, 0.5*(1.0 - x*y) as f32],
-                    engine::sphere(x, y, 0.0, 1.0)
-                )
-            );
-            
-            let _ = assembly.try_insert_element(
-                Point::new(
-                    format!("point{index_x}{index_y}"),
-                    format!("Point {index_x}{index_y}"),
-                    [0.5*(1.0 + x) as f32, 0.5*(1.0 + y) as f32, 0.5*(1.0 - x*y) as f32],
-                    engine::point(x, y, 0.0)
-                )
-            );
-        }
-    }
-}
-
-#[component]
-pub fn AddRemove() -> View {
-    /* DEBUG */
-    let assembly_name = create_signal("general".to_string());
-    create_effect(move || {
-        // get name of chosen assembly
-        let name = assembly_name.get_clone();
-        console::log_1(
-            &JsValue::from(format!("Showing assembly \"{}\"", name.clone()))
-        );
-        
-        batch(|| {
-            let state = use_context::<AppState>();
-            let assembly = &state.assembly;
-            
-            // clear state
-            assembly.regulators.update(|regs| regs.clear());
-            assembly.elements.update(|elts| elts.clear());
-            assembly.elements_by_id.update(|elts_by_id| elts_by_id.clear());
-            assembly.descent_history.set(DescentHistory::new());
-            state.selection.update(|sel| sel.clear());
-            
-            // load assembly
-            match name.as_str() {
-                "general" => load_gen_assemb(assembly),
-                "low-curv" => load_low_curv_assemb(assembly),
-                "pointed" => load_pointed_assemb(assembly),
-                _ => ()
-            };
-        });
-    });
-    
-    view! {
-        div(id="add-remove") {
-            button(
-                on:click=|_| {
-                    let state = use_context::<AppState>();
-                    state.assembly.insert_element_default::<Sphere>();
-                }
-            ) { "Add sphere" }
-            button(
-                on:click=|_| {
-                    let state = use_context::<AppState>();
-                    state.assembly.insert_element_default::<Point>();
-                }
-            ) { "Add point" }
-            button(
-                class="emoji", /* KLUDGE */ // for convenience, we're using an emoji as a temporary icon for this button
-                disabled={
-                    let state = use_context::<AppState>();
-                    state.selection.with(|sel| sel.len() != 2)
-                },
-                on:click=|_| {
-                    let state = use_context::<AppState>();
-                    let subjects: [_; 2] = state.selection.with(
-                        // the button is only enabled when two elements are
-                        // selected, so we know the cast to a two-element array
-                        // will succeed
-                        |sel| sel
-                            .clone()
-                            .into_iter()
-                            .collect::<Vec<_>>()
-                            .try_into()
-                            .unwrap()
-                    );
-                    state.assembly.insert_regulator(
-                        Rc::new(InversiveDistanceRegulator::new(subjects))
-                    );
-                    state.selection.update(|sel| sel.clear());
-                }
-            ) { "🔗" }
-            select(bind:value=assembly_name) { /* DEBUG */ // example assembly chooser
-                option(value="general") { "General" }
-                option(value="low-curv") { "Low-curvature" }
-                option(value="pointed") { "Pointed" }
-                option(value="empty") { "Empty" }
-            }
-        }
-    }
-}
\ No newline at end of file
diff --git a/app-proto/src/assembly.rs b/app-proto/src/assembly.rs
index c3b0c6b..94e7b3c 100644
--- a/app-proto/src/assembly.rs
+++ b/app-proto/src/assembly.rs
@@ -1,22 +1,21 @@
 use nalgebra::{DMatrix, DVector, DVectorView};
 use std::{
     cell::Cell,
-    collections::{BTreeMap, BTreeSet},
     cmp::Ordering,
+    collections::{BTreeMap, BTreeSet},
     fmt,
     fmt::{Debug, Formatter},
     hash::{Hash, Hasher},
     rc::Rc,
-    sync::{atomic, atomic::AtomicU64}
+    sync::{atomic, atomic::AtomicU64},
 };
 use sycamore::prelude::*;
 use web_sys::{console, wasm_bindgen::JsValue}; /* DEBUG */
 
 use crate::{
-    display::DisplayItem,
+    components::{display::DisplayItem, outline::OutlineItem},
     engine::{
         Q,
-        change_half_curvature,
         local_unif_to_std,
         point,
         project_point_to_normalized,
@@ -27,10 +26,9 @@ use crate::{
         ConfigSubspace,
         ConstraintProblem,
         DescentHistory,
-        Realization
+        Realization,
     },
-    outline::OutlineItem,
-    specified::SpecifiedValue
+    specified::SpecifiedValue,
 };
 
 pub type ElementColor = [f32; 3];
@@ -166,7 +164,7 @@ pub struct Sphere {
     pub ghost: Signal<bool>,
     pub regulators: Signal<BTreeSet<Rc<dyn Regulator>>>,
     serial: u64,
-    column_index: Cell<Option<usize>>
+    column_index: Cell<Option<usize>>,
 }
 
 impl Sphere {
@@ -176,17 +174,17 @@ impl Sphere {
         id: String,
         label: String,
         color: ElementColor,
-        representation: DVector<f64>
-    ) -> Sphere {
-        Sphere {
-            id: id,
-            label: label,
-            color: color,
+        representation: DVector<f64>,
+    ) -> Self {
+        Self {
+            id,
+            label,
+            color,
             representation: create_signal(representation),
             ghost: create_signal(false),
             regulators: create_signal(BTreeSet::new()),
             serial: Self::next_serial(),
-            column_index: None.into()
+            column_index: None.into(),
         }
     }
 }
@@ -196,12 +194,12 @@ impl Element for Sphere {
         "sphere".to_string()
     }
     
-    fn default(id: String, id_num: u64) -> Sphere {
-        Sphere::new(
+    fn default(id: String, id_num: u64) -> Self {
+        Self::new(
             id,
             format!("Sphere {id_num}"),
             [0.75_f32, 0.75_f32, 0.75_f32],
-            sphere(0.0, 0.0, 0.0, 1.0)
+            sphere(0.0, 0.0, 0.0, 1.0),
         )
     }
     
@@ -266,7 +264,7 @@ pub struct Point {
     pub ghost: Signal<bool>,
     pub regulators: Signal<BTreeSet<Rc<dyn Regulator>>>,
     serial: u64,
-    column_index: Cell<Option<usize>>
+    column_index: Cell<Option<usize>>,
 }
 
 impl Point {
@@ -276,9 +274,9 @@ impl Point {
         id: String,
         label: String,
         color: ElementColor,
-        representation: DVector<f64>
-    ) -> Point {
-        Point {
+        representation: DVector<f64>,
+    ) -> Self {
+        Self {
             id,
             label,
             color,
@@ -286,7 +284,7 @@ impl Point {
             ghost: create_signal(false),
             regulators: create_signal(BTreeSet::new()),
             serial: Self::next_serial(),
-            column_index: None.into()
+            column_index: None.into(),
         }
     }
 }
@@ -296,12 +294,12 @@ impl Element for Point {
         "point".to_string()
     }
     
-    fn default(id: String, id_num: u64) -> Point {
-        Point::new(
+    fn default(id: String, id_num: u64) -> Self {
+        Self::new(
             id,
             format!("Point {id_num}"),
             [0.75_f32, 0.75_f32, 0.75_f32],
-            point(0.0, 0.0, 0.0)
+            point(0.0, 0.0, 0.0),
         )
     }
     
@@ -350,7 +348,7 @@ impl ProblemPoser for Point {
             format!("Point \"{}\" should be indexed before writing problem data", self.id).as_str()
         );
         problem.gram.push_sym(index, index, 0.0);
-        problem.frozen.push(Point::WEIGHT_COMPONENT, index, 0.5);
+        problem.frozen.push(Self::WEIGHT_COMPONENT, index, 0.5);
         problem.guess.set_column(index, &self.representation.get_clone_untracked());
     }
 }
@@ -359,16 +357,6 @@ pub trait Regulator: Serial + ProblemPoser + OutlineItem {
     fn subjects(&self) -> Vec<Rc<dyn Element>>;
     fn measurement(&self) -> ReadSignal<f64>;
     fn set_point(&self) -> Signal<SpecifiedValue>;
-    
-    // this method is used to responsively precondition the assembly for
-    // realization when the regulator becomes a constraint, or is edited while
-    // acting as a constraint. it should track the set point, do any desired
-    // preconditioning when the set point is present, and use its return value
-    // to report whether the set is present. the default implementation does no
-    // preconditioning
-    fn try_activate(&self) -> bool {
-        self.set_point().with(|set_pt| set_pt.is_present())
-    }
 }
 
 impl Hash for dyn Regulator {
@@ -401,11 +389,11 @@ pub struct InversiveDistanceRegulator {
     pub subjects: [Rc<dyn Element>; 2],
     pub measurement: ReadSignal<f64>,
     pub set_point: Signal<SpecifiedValue>,
-    serial: u64
+    serial: u64,
 }
 
 impl InversiveDistanceRegulator {
-    pub fn new(subjects: [Rc<dyn Element>; 2]) -> InversiveDistanceRegulator {
+    pub fn new(subjects: [Rc<dyn Element>; 2]) -> Self {
         let representations = subjects.each_ref().map(|subj| subj.representation());
         let measurement = create_memo(move || {
             representations[0].with(|rep_0|
@@ -418,7 +406,7 @@ impl InversiveDistanceRegulator {
         let set_point = create_signal(SpecifiedValue::from_empty_spec());
         let serial = Self::next_serial();
         
-        InversiveDistanceRegulator { subjects, measurement, set_point, serial }
+        Self { subjects, measurement, set_point, serial }
     }
 }
 
@@ -461,11 +449,11 @@ pub struct HalfCurvatureRegulator {
     pub subject: Rc<dyn Element>,
     pub measurement: ReadSignal<f64>,
     pub set_point: Signal<SpecifiedValue>,
-    serial: u64
+    serial: u64,
 }
 
 impl HalfCurvatureRegulator {
-    pub fn new(subject: Rc<dyn Element>) -> HalfCurvatureRegulator {
+    pub fn new(subject: Rc<dyn Element>) -> Self {
         let measurement = subject.representation().map(
             |rep| rep[Sphere::CURVATURE_COMPONENT]
         );
@@ -473,7 +461,7 @@ impl HalfCurvatureRegulator {
         let set_point = create_signal(SpecifiedValue::from_empty_spec());
         let serial = Self::next_serial();
         
-        HalfCurvatureRegulator { subject, measurement, set_point, serial }
+        Self { subject, measurement, set_point, serial }
     }
 }
 
@@ -489,18 +477,6 @@ impl Regulator for HalfCurvatureRegulator {
     fn set_point(&self) -> Signal<SpecifiedValue> {
         self.set_point
     }
-    
-    fn try_activate(&self) -> bool {
-        match self.set_point.with(|set_pt| set_pt.value) {
-            Some(half_curv) => {
-                self.subject.representation().update(
-                    |rep| change_half_curvature(rep, half_curv)
-                );
-                true
-            }
-            None => false
-        }
-    }
 }
 
 impl Serial for HalfCurvatureRegulator {
@@ -525,7 +501,7 @@ impl ProblemPoser for HalfCurvatureRegulator {
 // the velocity is expressed in uniform coordinates
 pub struct ElementMotion<'a> {
     pub element: Rc<dyn Element>,
-    pub velocity: DVectorView<'a, f64>
+    pub velocity: DVectorView<'a, f64>,
 }
 
 type AssemblyMotion<'a> = Vec<ElementMotion<'a>>;
@@ -552,21 +528,42 @@ pub struct Assembly {
     // indexing
     pub elements_by_id: Signal<BTreeMap<String, Rc<dyn Element>>>,
     
+    // realization control
+    pub realization_trigger: Signal<()>,
+    
     // realization diagnostics
     pub realization_status: Signal<Result<(), String>>,
-    pub descent_history: Signal<DescentHistory>
+    pub descent_history: Signal<DescentHistory>,
 }
 
 impl Assembly {
     pub fn new() -> Assembly {
-        Assembly {
+        // create an assembly
+        let assembly = Assembly {
             elements: create_signal(BTreeSet::new()),
             regulators: create_signal(BTreeSet::new()),
             tangent: create_signal(ConfigSubspace::zero(0)),
             elements_by_id: create_signal(BTreeMap::default()),
+            realization_trigger: create_signal(()),
             realization_status: create_signal(Ok(())),
-            descent_history: create_signal(DescentHistory::new())
-        }
+            descent_history: create_signal(DescentHistory::new()),
+        };
+        
+        // realize the assembly whenever the element list, the regulator list,
+        // a regulator's set point, or the realization trigger is updated
+        let assembly_for_effect = assembly.clone();
+        create_effect(move || {
+            assembly_for_effect.elements.track();
+            assembly_for_effect.regulators.with(
+                |regs| for reg in regs {
+                    reg.set_point().track();
+                }
+            );
+            assembly_for_effect.realization_trigger.track();
+            assembly_for_effect.realize();
+        });
+        
+        assembly
     }
     
     // --- inserting elements and regulators ---
@@ -627,19 +624,6 @@ impl Assembly {
             regulators.update(|regs| regs.insert(regulator.clone()));
         }
         
-        // update the realization when the regulator becomes a constraint, or is
-        // edited while acting as a constraint
-        let self_for_effect = self.clone();
-        create_effect(move || {
-            /* DEBUG */
-            // log the regulator update
-            console_log!("Updated regulator with subjects {:?}", regulator.subjects());
-            
-            if regulator.try_activate() {
-                self_for_effect.realize();
-            }
-        });
-        
         /* DEBUG */
         // print an updated list of regulators
         console_log!("Regulators:");
@@ -707,8 +691,10 @@ impl Assembly {
         } else {
             console_log!("✅️ Target accuracy achieved!");
         }
-        console_log!("Steps: {}", history.scaled_loss.len() - 1);
-        console_log!("Loss: {}", history.scaled_loss.last().unwrap());
+        if history.scaled_loss.len() > 0 {
+            console_log!("Steps: {}", history.scaled_loss.len() - 1);
+            console_log!("Loss: {}", history.scaled_loss.last().unwrap());
+        }
         
         // report the loss history
         self.descent_history.set(history);
@@ -738,7 +724,7 @@ impl Assembly {
                 // `Err(message)` we received from the match: we're changing the
                 // `Ok` type from `Realization` to `()`
                 self.realization_status.set(Err(message))
-            }
+            },
         }
     }
     
@@ -821,15 +807,15 @@ impl Assembly {
                     },
                     None => {
                         console_log!("No velocity to unpack for fresh element \"{}\"", elt.id())
-                    }
+                    },
                 };
             });
         }
         
-        // bring the configuration back onto the solution variety. this also
-        // gets the elements' column indices and the saved tangent space back in
-        // sync
-        self.realize();
+        // trigger a realization to bring the configuration back onto the
+        // solution variety. this also gets the elements' column indices and the
+        // saved tangent space back in sync
+        self.realization_trigger.set(());
     }
 }
 
@@ -881,7 +867,7 @@ mod tests {
                     String::from(sphere_id),
                     String::from("Sphere 0"),
                     [0.75_f32, 0.75_f32, 0.75_f32],
-                    engine::sphere(0.0, 0.0, 0.0, INITIAL_RADIUS)
+                    engine::sphere(0.0, 0.0, 0.0, INITIAL_RADIUS),
                 )
             );
             
@@ -895,7 +881,7 @@ mod tests {
                     vec![
                         ElementMotion {
                             element: sphere.clone(),
-                            velocity: velocity.as_view()
+                            velocity: velocity.as_view(),
                         }
                     ]
                 );
diff --git a/app-proto/src/components.rs b/app-proto/src/components.rs
new file mode 100644
index 0000000..7387d58
--- /dev/null
+++ b/app-proto/src/components.rs
@@ -0,0 +1,5 @@
+pub mod add_remove;
+pub mod diagnostics;
+pub mod display;
+pub mod outline;
+pub mod test_assembly_chooser;
\ No newline at end of file
diff --git a/app-proto/src/components/add_remove.rs b/app-proto/src/components/add_remove.rs
new file mode 100644
index 0000000..4196640
--- /dev/null
+++ b/app-proto/src/components/add_remove.rs
@@ -0,0 +1,69 @@
+use std::rc::Rc;
+use sycamore::prelude::*;
+
+use super::test_assembly_chooser::TestAssemblyChooser;
+use crate::{
+    AppState,
+    assembly::{InversiveDistanceRegulator, Point, Sphere},
+};
+
+#[component]
+pub fn AddRemove() -> View {
+    view! {
+        div(id = "add-remove") {
+            button(
+                on:click = |_| {
+                    let state = use_context::<AppState>();
+                    batch(|| {
+                        // this call is batched to avoid redundant realizations.
+                        // it updates the element list and the regulator list,
+                        // which are both tracked by the realization effect
+                        /* TO DO */
+                        // it would make more to do the batching inside
+                        // `insert_element_default`, but that will have to wait
+                        // until Sycamore handles nested batches correctly.
+                        //
+                        //   https://github.com/sycamore-rs/sycamore/issues/802
+                        //
+                        // the nested batch issue is relevant here because the
+                        // assembly loaders in the test assembly chooser use
+                        // `insert_element_default` within larger batches
+                        state.assembly.insert_element_default::<Sphere>();
+                    });
+                }
+            ) { "Add sphere" }
+            button(
+                on:click = |_| {
+                    let state = use_context::<AppState>();
+                    state.assembly.insert_element_default::<Point>();
+                }
+            ) { "Add point" }
+            button(
+                class = "emoji", /* KLUDGE */ // for convenience, we're using an emoji as a temporary icon for this button
+                disabled = {
+                    let state = use_context::<AppState>();
+                    state.selection.with(|sel| sel.len() != 2)
+                },
+                on:click = |_| {
+                    let state = use_context::<AppState>();
+                    let subjects: [_; 2] = state.selection.with(
+                        // the button is only enabled when two elements are
+                        // selected, so we know the cast to a two-element array
+                        // will succeed
+                        |sel| sel
+                            .clone()
+                            .into_iter()
+                            .collect::<Vec<_>>()
+                            .try_into()
+                            .unwrap()
+                    );
+                    state.assembly.insert_regulator(
+                        Rc::new(InversiveDistanceRegulator::new(subjects))
+                    );
+                    state.selection.update(|sel| sel.clear());
+                }
+            ) { "🔗" }
+            TestAssemblyChooser {}
+        }
+    }
+}
\ No newline at end of file
diff --git a/app-proto/src/diagnostics.rs b/app-proto/src/components/diagnostics.rs
similarity index 88%
rename from app-proto/src/diagnostics.rs
rename to app-proto/src/components/diagnostics.rs
index a2f090a..e265982 100644
--- a/app-proto/src/diagnostics.rs
+++ b/app-proto/src/components/diagnostics.rs
@@ -11,14 +11,12 @@ use crate::AppState;
 
 #[derive(Clone)]
 struct DiagnosticsState {
-    active_tab: Signal<String>
+    active_tab: Signal<String>,
 }
 
 impl DiagnosticsState {
-    fn new(initial_tab: String) -> DiagnosticsState {
-        DiagnosticsState {
-            active_tab: create_signal(initial_tab)
-        }
+    fn new(initial_tab: String) -> Self {
+        Self { active_tab: create_signal(initial_tab) }
     }
 }
 
@@ -29,20 +27,20 @@ fn RealizationStatus() -> View {
     let realization_status = state.assembly.realization_status;
     view! {
         div(
-            id="realization-status",
-            class=realization_status.with(
+            id = "realization-status",
+            class = realization_status.with(
                 |status| match status {
                     Ok(_) => "",
-                    Err(_) => "invalid"
+                    Err(_) => "invalid",
                 }
             )
         ) {
-            div(class="status")
+            div(class = "status")
             div {
                 (realization_status.with(
                     |status| match status {
                         Ok(_) => "Target accuracy achieved".to_string(),
-                        Err(message) => message.clone()
+                        Err(message) => message.clone(),
                     }
                 ))
             }
@@ -53,7 +51,7 @@ fn RealizationStatus() -> View {
 fn into_log10_time_point((step, value): (usize, f64)) -> Vec<Option<f64>> {
     vec![
         Some(step as f64),
-        if value == 0.0 { None } else { Some(value.abs().log10()) }
+        if value == 0.0 { None } else { Some(value.abs().log10()) },
     ]
 }
 
@@ -105,7 +103,7 @@ fn LossHistory() -> View {
     });
     
     view! {
-        div(id=CONTAINER_ID, class="diagnostics-chart")
+        div(id = CONTAINER_ID, class = "diagnostics-chart")
     }
 }
 
@@ -122,7 +120,7 @@ fn SpectrumHistory() -> View {
             // positive, negative, and strictly-zero parts
             let (
                 hess_eigvals_zero,
-                hess_eigvals_nonzero
+                hess_eigvals_nonzero,
             ): (Vec<_>, Vec<_>) = state.assembly.descent_history.with(
                 |history| history.hess_eigvals
                     .iter()
@@ -143,7 +141,7 @@ fn SpectrumHistory() -> View {
                 .unwrap_or(1.0);
             let (
                 hess_eigvals_pos,
-                hess_eigvals_neg
+                hess_eigvals_neg,
             ): (Vec<_>, Vec<_>) = hess_eigvals_nonzero
                 .into_iter()
                 .partition(|&(_, val)| val > 0.0);
@@ -211,7 +209,7 @@ fn SpectrumHistory() -> View {
     });
     
     view! {
-        div(id=CONTAINER_ID, class="diagnostics-chart")
+        div(id = CONTAINER_ID, class = "diagnostics-chart")
     }
 }
 
@@ -220,8 +218,8 @@ fn DiagnosticsPanel(name: &'static str, children: Children) -> View {
     let diagnostics_state = use_context::<DiagnosticsState>();
     view! {
         div(
-            class="diagnostics-panel",
-            "hidden"=diagnostics_state.active_tab.with(
+            class = "diagnostics-panel",
+            "hidden" = diagnostics_state.active_tab.with(
                 |active_tab| {
                     if active_tab == name {
                         None
@@ -243,16 +241,16 @@ pub fn Diagnostics() -> View {
     provide_context(diagnostics_state);
     
     view! {
-        div(id="diagnostics") {
-            div(id="diagnostics-bar") {
+        div(id = "diagnostics") {
+            div(id = "diagnostics-bar") {
                 RealizationStatus {}
-                select(bind:value=active_tab) {
-                    option(value="loss") { "Loss" }
-                    option(value="spectrum") { "Spectrum" }
+                select(bind:value = active_tab) {
+                    option(value = "loss") { "Loss" }
+                    option(value = "spectrum") { "Spectrum" }
                 }
             }
-            DiagnosticsPanel(name="loss") { LossHistory {} }
-            DiagnosticsPanel(name="spectrum") { SpectrumHistory {} }
+            DiagnosticsPanel(name = "loss") { LossHistory {} }
+            DiagnosticsPanel(name = "spectrum") { SpectrumHistory {} }
         }
     }
 }
\ No newline at end of file
diff --git a/app-proto/src/display.rs b/app-proto/src/components/display.rs
similarity index 93%
rename from app-proto/src/display.rs
rename to app-proto/src/components/display.rs
index 1646c4e..da921dd 100644
--- a/app-proto/src/display.rs
+++ b/app-proto/src/components/display.rs
@@ -12,12 +12,12 @@ use web_sys::{
     WebGlProgram,
     WebGlShader,
     WebGlUniformLocation,
-    wasm_bindgen::{JsCast, JsValue}
+    wasm_bindgen::{JsCast, JsValue},
 };
 
 use crate::{
     AppState,
-    assembly::{Element, ElementColor, ElementMotion, Point, Sphere}
+    assembly::{Element, ElementColor, ElementMotion, Point, Sphere},
 };
 
 // --- color ---
@@ -37,15 +37,15 @@ fn combine_channels(color: ElementColor, opacity: f32) -> ColorWithOpacity {
 struct SceneSpheres {
     representations: Vec<DVector<f64>>,
     colors_with_opacity: Vec<ColorWithOpacity>,
-    highlights: Vec<f32>
+    highlights: Vec<f32>,
 }
 
 impl SceneSpheres {
-    fn new() -> SceneSpheres{
-        SceneSpheres {
+    fn new() -> Self {
+        Self {
             representations: Vec::new(),
             colors_with_opacity: Vec::new(),
-            highlights: Vec::new()
+            highlights: Vec::new(),
         }
     }
     
@@ -53,7 +53,10 @@ impl SceneSpheres {
         self.representations.len().try_into().expect("Number of spheres must fit in a 32-bit integer")
     }
     
-    fn push(&mut self, representation: DVector<f64>, color: ElementColor, opacity: f32, highlight: f32) {
+    fn push(
+        &mut self, representation: DVector<f64>,
+        color: ElementColor, opacity: f32, highlight: f32,
+    ) {
         self.representations.push(representation);
         self.colors_with_opacity.push(combine_channels(color, opacity));
         self.highlights.push(highlight);
@@ -64,20 +67,23 @@ struct ScenePoints {
     representations: Vec<DVector<f64>>,
     colors_with_opacity: Vec<ColorWithOpacity>,
     highlights: Vec<f32>,
-    selections: Vec<f32>
+    selections: Vec<f32>,
 }
 
 impl ScenePoints {
-    fn new() -> ScenePoints {
-        ScenePoints {
+    fn new() -> Self {
+        Self {
             representations: Vec::new(),
             colors_with_opacity: Vec::new(),
             highlights: Vec::new(),
-            selections: Vec::new()
+            selections: Vec::new(),
         }
     }
     
-    fn push(&mut self, representation: DVector<f64>, color: ElementColor, opacity: f32, highlight: f32, selected: bool) {
+    fn push(
+        &mut self, representation: DVector<f64>,
+        color: ElementColor, opacity: f32, highlight: f32, selected: bool,
+    ) {
         self.representations.push(representation);
         self.colors_with_opacity.push(combine_channels(color, opacity));
         self.highlights.push(highlight);
@@ -87,14 +93,14 @@ impl ScenePoints {
 
 pub struct Scene {
     spheres: SceneSpheres,
-    points: ScenePoints
+    points: ScenePoints,
 }
 
 impl Scene {
-    fn new() -> Scene {
-        Scene {
+    fn new() -> Self {
+        Self {
             spheres: SceneSpheres::new(),
-            points: ScenePoints::new()
+            points: ScenePoints::new(),
         }
     }
 }
@@ -105,7 +111,12 @@ pub trait DisplayItem {
     // the smallest positive depth, represented as a multiple of `dir`, where
     // the line generated by `dir` hits the element. returns `None` if the line
     // misses the element
-    fn cast(&self, dir: Vector3<f64>, assembly_to_world: &DMatrix<f64>, pixel_size: f64) -> Option<f64>;
+    fn cast(
+        &self,
+        dir: Vector3<f64>,
+        assembly_to_world: &DMatrix<f64>,
+        pixel_size: f64,
+    ) -> Option<f64>;
 }
 
 impl DisplayItem for Sphere {
@@ -124,7 +135,12 @@ impl DisplayItem for Sphere {
     
     // this method should be kept synchronized with `sphere_cast` in
     // `spheres.frag`, which does essentially the same thing on the GPU side
-    fn cast(&self, dir: Vector3<f64>, assembly_to_world: &DMatrix<f64>, _pixel_size: f64) -> Option<f64> {
+    fn cast(
+        &self,
+        dir: Vector3<f64>,
+        assembly_to_world: &DMatrix<f64>,
+        _pixel_size: f64,
+    ) -> Option<f64> {
         // if `a/b` is less than this threshold, we approximate
         // `a*u^2 + b*u + c` by the linear function `b*u + c`
         const DEG_THRESHOLD: f64 = 1e-9;
@@ -177,7 +193,12 @@ impl DisplayItem for Point {
     }
     
     /* SCAFFOLDING */
-    fn cast(&self, dir: Vector3<f64>, assembly_to_world: &DMatrix<f64>, pixel_size: f64) -> Option<f64> {
+    fn cast(
+        &self,
+        dir: Vector3<f64>,
+        assembly_to_world: &DMatrix<f64>,
+        pixel_size: f64,
+    ) -> Option<f64> {
         let rep = self.representation.with_untracked(|rep| assembly_to_world * rep);
         if rep[2] < 0.0 {
             // this constant should be kept synchronized with `point.frag`
@@ -220,7 +241,7 @@ fn compile_shader(
 fn set_up_program(
     context: &WebGl2RenderingContext,
     vertex_shader_source: &str,
-    fragment_shader_source: &str
+    fragment_shader_source: &str,
 ) -> WebGlProgram {
     // compile the shaders
     let vertex_shader = compile_shader(
@@ -260,12 +281,12 @@ fn get_uniform_array_locations<const N: usize>(
     context: &WebGl2RenderingContext,
     program: &WebGlProgram,
     var_name: &str,
-    member_name_opt: Option<&str>
+    member_name_opt: Option<&str>,
 ) -> [Option<WebGlUniformLocation>; N] {
     array::from_fn(|n| {
         let name = match member_name_opt {
             Some(member_name) => format!("{var_name}[{n}].{member_name}"),
-            None => format!("{var_name}[{n}]")
+            None => format!("{var_name}[{n}]"),
         };
         context.get_uniform_location(&program, name.as_str())
     })
@@ -276,7 +297,7 @@ fn bind_to_attribute(
     context: &WebGl2RenderingContext,
     attr_index: u32,
     attr_size: i32,
-    buffer: &Option<WebGlBuffer>
+    buffer: &Option<WebGlBuffer>,
 ) {
     context.bind_buffer(WebGl2RenderingContext::ARRAY_BUFFER, buffer.as_ref());
     context.vertex_attrib_pointer_with_i32(
@@ -292,7 +313,7 @@ fn bind_to_attribute(
 // load the given data into a new vertex buffer object
 fn load_new_buffer(
     context: &WebGl2RenderingContext,
-    data: &[f32]
+    data: &[f32],
 ) -> Option<WebGlBuffer> {
     // create a buffer and bind it to ARRAY_BUFFER
     let buffer = context.create_buffer();
@@ -319,7 +340,7 @@ fn bind_new_buffer_to_attribute(
     context: &WebGl2RenderingContext,
     attr_index: u32,
     attr_size: i32,
-    data: &[f32]
+    data: &[f32],
 ) {
     let buffer = load_new_buffer(context, data);
     bind_to_attribute(context, attr_index, attr_size, &buffer);
@@ -341,9 +362,9 @@ fn event_dir(event: &MouseEvent) -> (Vector3<f64>, f64) {
         Vector3::new(
             FOCAL_SLOPE * (2.0*(f64::from(event.client_x()) - rect.left()) - width) / shortdim,
             FOCAL_SLOPE * (2.0*(rect.bottom() - f64::from(event.client_y())) - height) / shortdim,
-            -1.0
+            -1.0,
         ),
-        FOCAL_SLOPE * 2.0 / shortdim
+        FOCAL_SLOPE * 2.0 / shortdim,
     )
 }
 
@@ -443,14 +464,14 @@ pub fn Display() -> View {
         let sphere_program = set_up_program(
             &ctx,
             include_str!("identity.vert"),
-            include_str!("spheres.frag")
+            include_str!("spheres.frag"),
         );
         
         // set up the point rendering program
         let point_program = set_up_program(
             &ctx,
             include_str!("point.vert"),
-            include_str!("point.frag")
+            include_str!("point.frag"),
         );
         
         /* DEBUG */
@@ -467,7 +488,7 @@ pub fn Display() -> View {
         // capped at 1024 elements
         console::log_2(
             &ctx.get_parameter(WebGl2RenderingContext::MAX_FRAGMENT_UNIFORM_VECTORS).unwrap(),
-            &JsValue::from("uniform vectors available")
+            &JsValue::from("uniform vectors available"),
         );
         
         // find the sphere program's vertex attribute
@@ -503,7 +524,7 @@ pub fn Display() -> View {
             // southeast triangle
             -1.0, -1.0, 0.0,
              1.0,  1.0, 0.0,
-             1.0, -1.0, 0.0
+             1.0, -1.0, 0.0,
         ];
         let viewport_position_buffer = load_new_buffer(&ctx, &viewport_positions);
         
@@ -596,7 +617,7 @@ pub fn Display() -> View {
                         vec![
                             ElementMotion {
                                 element: sel,
-                                velocity: elt_motion.as_view()
+                                velocity: elt_motion.as_view(),
                             }
                         ]
                     );
@@ -629,7 +650,7 @@ pub fn Display() -> View {
                         0.0, 1.0,   0.0, 0.0, 0.0,
                         0.0, 0.0,   1.0, 0.0,   u,
                         0.0, 0.0, 2.0*u, 1.0, u*u,
-                        0.0, 0.0,   0.0, 0.0, 1.0
+                        0.0, 0.0,   0.0, 0.0, 1.0,
                     ])
                 };
                 let asm_to_world = &location * &orientation;
@@ -668,19 +689,19 @@ pub fn Display() -> View {
                     let v = &sphere_reps_world[n];
                     ctx.uniform3fv_with_f32_array(
                         sphere_sp_locs[n].as_ref(),
-                        v.rows(0, 3).as_slice()
+                        v.rows(0, 3).as_slice(),
                     );
                     ctx.uniform2fv_with_f32_array(
                         sphere_lt_locs[n].as_ref(),
-                        v.rows(3, 2).as_slice()
+                        v.rows(3, 2).as_slice(),
                     );
                     ctx.uniform4fv_with_f32_array(
                         sphere_color_locs[n].as_ref(),
-                        &scene.spheres.colors_with_opacity[n]
+                        &scene.spheres.colors_with_opacity[n],
                     );
                     ctx.uniform1f(
                         sphere_highlight_locs[n].as_ref(),
-                        scene.spheres.highlights[n]
+                        scene.spheres.highlights[n],
                     );
                 }
                 
@@ -773,7 +794,7 @@ pub fn Display() -> View {
             "ArrowLeft" if shift => roll_ccw.set(value),
             "ArrowRight" => yaw_right.set(value),
             "ArrowLeft" => yaw_left.set(value),
-            _ => navigating = false
+            _ => navigating = false,
         };
         if navigating {
             scene_changed.set(true);
@@ -793,7 +814,7 @@ pub fn Display() -> View {
             "s" | "S" => translate_neg_y.set(value),
             "]" | "}" => shrink_neg.set(value),
             "[" | "{" => shrink_pos.set(value),
-            _ => manipulating = false
+            _ => manipulating = false,
         };
         if manipulating {
             event.prevent_default();
@@ -805,12 +826,12 @@ pub fn Display() -> View {
         // switch back to integer-valued parameters when that becomes possible
         // again
         canvas(
-            ref=display,
-            id="display",
-            width="600",
-            height="600",
-            tabindex="0",
-            on:keydown=move |event: KeyboardEvent| {
+            ref = display,
+            id = "display",
+            width = "600",
+            height = "600",
+            tabindex = "0",
+            on:keydown = move |event: KeyboardEvent| {
                 if event.key() == "Shift" {
                     // swap navigation inputs
                     roll_cw.set(yaw_right.get());
@@ -836,7 +857,7 @@ pub fn Display() -> View {
                     set_manip_signal(&event, 1.0);
                 }
             },
-            on:keyup=move |event: KeyboardEvent| {
+            on:keyup = move |event: KeyboardEvent| {
                 if event.key() == "Shift" {
                     // swap navigation inputs
                     yaw_right.set(roll_cw.get());
@@ -858,7 +879,7 @@ pub fn Display() -> View {
                     set_manip_signal(&event, 0.0);
                 }
             },
-            on:blur=move |_| {
+            on:blur = move |_| {
                 pitch_up.set(0.0);
                 pitch_down.set(0.0);
                 yaw_right.set(0.0);
@@ -866,7 +887,7 @@ pub fn Display() -> View {
                 roll_ccw.set(0.0);
                 roll_cw.set(0.0);
             },
-            on:click=move |event: MouseEvent| {
+            on:click = move |event: MouseEvent| {
                 // find the nearest element along the pointer direction
                 let (dir, pixel_size) = event_dir(&event);
                 console::log_1(&JsValue::from(dir.to_string()));
@@ -883,18 +904,18 @@ pub fn Display() -> View {
                                     clicked = Some((elt, depth))
                                 }
                             },
-                            None => clicked = Some((elt, depth))
-                        }
-                        None => ()
+                            None => clicked = Some((elt, depth)),
+                        },
+                        None => (),
                     };
                 }
                 
                 // if we clicked something, select it
                 match clicked {
                     Some((elt, _)) => state.select(&elt, event.shift_key()),
-                    None => state.selection.update(|sel| sel.clear())
+                    None => state.selection.update(|sel| sel.clear()),
                 };
-            }
+            },
         )
     }
 }
\ No newline at end of file
diff --git a/app-proto/src/identity.vert b/app-proto/src/components/identity.vert
similarity index 100%
rename from app-proto/src/identity.vert
rename to app-proto/src/components/identity.vert
diff --git a/app-proto/src/outline.rs b/app-proto/src/components/outline.rs
similarity index 76%
rename from app-proto/src/outline.rs
rename to app-proto/src/components/outline.rs
index 77d8575..5355042 100644
--- a/app-proto/src/outline.rs
+++ b/app-proto/src/components/outline.rs
@@ -1,11 +1,7 @@
 use itertools::Itertools;
 use std::rc::Rc;
 use sycamore::prelude::*;
-use web_sys::{
-    KeyboardEvent,
-    MouseEvent,
-    wasm_bindgen::JsCast
-};
+use web_sys::{KeyboardEvent, MouseEvent, wasm_bindgen::JsCast};
 
 use crate::{
     AppState,
@@ -13,7 +9,7 @@ use crate::{
         Element,
         HalfCurvatureRegulator,
         InversiveDistanceRegulator,
-        Regulator
+        Regulator,
     },
     specified::SpecifiedValue
 };
@@ -49,8 +45,8 @@ fn RegulatorInput(regulator: Rc<dyn Regulator>) -> View {
     
     view! {
         input(
-            r#type="text",
-            class=move || {
+            r#type = "text",
+            class = move || {
                 if valid.get() {
                     set_point.with(|set_pt| {
                         if set_pt.is_present() {
@@ -63,27 +59,27 @@ fn RegulatorInput(regulator: Rc<dyn Regulator>) -> View {
                     "regulator-input invalid"
                 }
             },
-            placeholder=measurement.with(|result| result.to_string()),
-            bind:value=value,
-            on:change=move |_| {
+            placeholder = measurement.with(|result| result.to_string()),
+            bind:value = value,
+            on:change = move |_| {
                 valid.set(
                     match SpecifiedValue::try_from(value.get_clone_untracked()) {
                         Ok(set_pt) => {
                             set_point.set(set_pt);
                             true
-                        }
-                        Err(_) => false
+                        },
+                        Err(_) => false,
                     }
                 )
             },
-            on:keydown={
+            on:keydown = {
                 move |event: KeyboardEvent| {
                     match event.key().as_str() {
                         "Escape" => reset_value(),
-                        _ => ()
+                        _ => (),
                     }
                 }
-            }
+            },
         )
     }
 }
@@ -100,11 +96,11 @@ impl OutlineItem for InversiveDistanceRegulator {
             self.subjects[0].label()
         }.clone();
         view! {
-            li(class="regulator") {
-                div(class="regulator-label") { (other_subject_label) }
-                div(class="regulator-type") { "Inversive distance" }
-                RegulatorInput(regulator=self)
-                div(class="status")
+            li(class = "regulator") {
+                div(class = "regulator-label") { (other_subject_label) }
+                div(class = "regulator-type") { "Inversive distance" }
+                RegulatorInput(regulator = self)
+                div(class = "status")
             }
         }
     }
@@ -113,11 +109,11 @@ impl OutlineItem for InversiveDistanceRegulator {
 impl OutlineItem for HalfCurvatureRegulator {
     fn outline_item(self: Rc<Self>, _element: &Rc<dyn Element>) -> View {
         view! {
-            li(class="regulator") {
-                div(class="regulator-label") // for spacing
-                div(class="regulator-type") { "Half-curvature" }
-                RegulatorInput(regulator=self)
-                div(class="status")
+            li(class = "regulator") {
+                div(class = "regulator-label") // for spacing
+                div(class = "regulator-type") { "Half-curvature" }
+                RegulatorInput(regulator = self)
+                div(class = "status")
             }
         }
     }
@@ -156,10 +152,10 @@ fn ElementOutlineItem(element: Rc<dyn Element>) -> View {
     let details_node = create_node_ref();
     view! {
         li {
-            details(ref=details_node) {
+            details(ref = details_node) {
                 summary(
-                    class=class.get(),
-                    on:keydown={
+                    class = class.get(),
+                    on:keydown = {
                         let element_for_handler = element.clone();
                         move |event: KeyboardEvent| {
                             match event.key().as_str() {
@@ -179,18 +175,18 @@ fn ElementOutlineItem(element: Rc<dyn Element>) -> View {
                                         .unchecked_into::<web_sys::Element>()
                                         .remove_attribute("open");
                                 },
-                                _ => ()
+                                _ => (),
                             }
                         }
                     }
                 ) {
                     div(
-                        class="element-switch",
-                        on:click=|event: MouseEvent| event.stop_propagation()
+                        class = "element-switch",
+                        on:click = |event: MouseEvent| event.stop_propagation()
                     )
                     div(
-                        class="element",
-                        on:click={
+                        class = "element",
+                        on:click = {
                             let state_for_handler = state.clone();
                             let element_for_handler = element.clone();
                             move |event: MouseEvent| {
@@ -200,20 +196,20 @@ fn ElementOutlineItem(element: Rc<dyn Element>) -> View {
                             }
                         }
                     ) {
-                        div(class="element-label") { (label) }
-                        div(class="element-representation") { (rep_components) }
+                        div(class = "element-label") { (label) }
+                        div(class = "element-representation") { (rep_components) }
                         input(
-                            r#type="checkbox",
-                            bind:checked=element.ghost(),
-                            on:click=|event: MouseEvent| event.stop_propagation()
+                            r#type = "checkbox",
+                            bind:checked = element.ghost(),
+                            on:click = |event: MouseEvent| event.stop_propagation()
                         )
                     }
                 }
-                ul(class="regulators") {
+                ul(class = "regulators") {
                     Keyed(
-                        list=regulator_list,
-                        view=move |reg| reg.outline_item(&element),
-                        key=|reg| reg.serial()
+                        list = regulator_list,
+                        view = move |reg| reg.outline_item(&element),
+                        key = |reg| reg.serial()
                     )
                 }
             }
@@ -246,18 +242,18 @@ pub fn Outline() -> View {
     
     view! {
         ul(
-            id="outline",
-            on:click={
+            id = "outline",
+            on:click = {
                 let state = use_context::<AppState>();
                 move |_| state.selection.update(|sel| sel.clear())
             }
         ) {
             Keyed(
-                list=element_list,
-                view=|elt| view! {
-                    ElementOutlineItem(element=elt)
+                list = element_list,
+                view = |elt| view! {
+                    ElementOutlineItem(element = elt)
                 },
-                key=|elt| elt.serial()
+                key = |elt| elt.serial()
             )
         }
     }
diff --git a/app-proto/src/point.frag b/app-proto/src/components/point.frag
similarity index 100%
rename from app-proto/src/point.frag
rename to app-proto/src/components/point.frag
diff --git a/app-proto/src/point.vert b/app-proto/src/components/point.vert
similarity index 100%
rename from app-proto/src/point.vert
rename to app-proto/src/components/point.vert
diff --git a/app-proto/src/spheres.frag b/app-proto/src/components/spheres.frag
similarity index 100%
rename from app-proto/src/spheres.frag
rename to app-proto/src/components/spheres.frag
diff --git a/app-proto/src/components/test_assembly_chooser.rs b/app-proto/src/components/test_assembly_chooser.rs
new file mode 100644
index 0000000..0d387d3
--- /dev/null
+++ b/app-proto/src/components/test_assembly_chooser.rs
@@ -0,0 +1,941 @@
+use itertools::izip;
+use std::{f64::consts::{FRAC_1_SQRT_2, PI}, rc::Rc};
+use nalgebra::Vector3;
+use sycamore::prelude::*;
+use web_sys::{console, wasm_bindgen::JsValue};
+
+use crate::{
+    AppState,
+    assembly::{
+        Assembly,
+        Element,
+        ElementColor,
+        InversiveDistanceRegulator,
+        Point,
+        Sphere,
+    },
+    engine,
+    engine::DescentHistory,
+    specified::SpecifiedValue,
+};
+
+// --- loaders ---
+
+/* DEBUG */
+// each of these functions loads an example assembly for testing. once we've
+// done more work on saving and loading assemblies, we should come back to this
+// code to see if it can be simplified
+
+fn load_general(assembly: &Assembly) {
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            String::from("gemini_a"),
+            String::from("Castor"),
+            [1.00_f32, 0.25_f32, 0.00_f32],
+            engine::sphere(0.5, 0.5, 0.0, 1.0),
+        )
+    );
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            String::from("gemini_b"),
+            String::from("Pollux"),
+            [0.00_f32, 0.25_f32, 1.00_f32],
+            engine::sphere(-0.5, -0.5, 0.0, 1.0),
+        )
+    );
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            String::from("ursa_major"),
+            String::from("Ursa major"),
+            [0.25_f32, 0.00_f32, 1.00_f32],
+            engine::sphere(-0.5, 0.5, 0.0, 0.75),
+        )
+    );
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            String::from("ursa_minor"),
+            String::from("Ursa minor"),
+            [0.25_f32, 1.00_f32, 0.00_f32],
+            engine::sphere(0.5, -0.5, 0.0, 0.5),
+        )
+    );
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            String::from("moon_deimos"),
+            String::from("Deimos"),
+            [0.75_f32, 0.75_f32, 0.00_f32],
+            engine::sphere(0.0, 0.15, 1.0, 0.25),
+        )
+    );
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            String::from("moon_phobos"),
+            String::from("Phobos"),
+            [0.00_f32, 0.75_f32, 0.50_f32],
+            engine::sphere(0.0, -0.15, -1.0, 0.25),
+        )
+    );
+}
+
+fn load_low_curvature(assembly: &Assembly) {
+    // create the spheres
+    let a = 0.75_f64.sqrt();
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            "central".to_string(),
+            "Central".to_string(),
+            [0.75_f32, 0.75_f32, 0.75_f32],
+            engine::sphere(0.0, 0.0, 0.0, 1.0),
+        )
+    );
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            "assemb_plane".to_string(),
+            "Assembly plane".to_string(),
+            [0.75_f32, 0.75_f32, 0.75_f32],
+            engine::sphere_with_offset(0.0, 0.0, 1.0, 0.0, 0.0),
+        )
+    );
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            "side1".to_string(),
+            "Side 1".to_string(),
+            [1.00_f32, 0.00_f32, 0.25_f32],
+            engine::sphere_with_offset(1.0, 0.0, 0.0, 1.0, 0.0),
+        )
+    );
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            "side2".to_string(),
+            "Side 2".to_string(),
+            [0.25_f32, 1.00_f32, 0.00_f32],
+            engine::sphere_with_offset(-0.5, a, 0.0, 1.0, 0.0),
+        )
+    );
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            "side3".to_string(),
+            "Side 3".to_string(),
+            [0.00_f32, 0.25_f32, 1.00_f32],
+            engine::sphere_with_offset(-0.5, -a, 0.0, 1.0, 0.0),
+        )
+    );
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            "corner1".to_string(),
+            "Corner 1".to_string(),
+            [0.75_f32, 0.75_f32, 0.75_f32],
+            engine::sphere(-4.0/3.0, 0.0, 0.0, 1.0/3.0),
+        )
+    );
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            "corner2".to_string(),
+            "Corner 2".to_string(),
+            [0.75_f32, 0.75_f32, 0.75_f32],
+            engine::sphere(2.0/3.0, -4.0/3.0 * a, 0.0, 1.0/3.0),
+        )
+    );
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            String::from("corner3"),
+            String::from("Corner 3"),
+            [0.75_f32, 0.75_f32, 0.75_f32],
+            engine::sphere(2.0/3.0, 4.0/3.0 * a, 0.0, 1.0/3.0),
+        )
+    );
+    
+    // impose the desired tangencies and make the sides planar
+    let index_range = 1..=3;
+    let [central, assemb_plane] = ["central", "assemb_plane"].map(
+        |id| assembly.elements_by_id.with_untracked(
+            |elts_by_id| elts_by_id[id].clone()
+        )
+    );
+    let sides = index_range.clone().map(
+        |k| assembly.elements_by_id.with_untracked(
+            |elts_by_id| elts_by_id[&format!("side{k}")].clone()
+        )
+    );
+    let corners = index_range.map(
+        |k| assembly.elements_by_id.with_untracked(
+            |elts_by_id| elts_by_id[&format!("corner{k}")].clone()
+        )
+    );
+    for plane in [assemb_plane.clone()].into_iter().chain(sides.clone()) {
+        // fix the curvature of each plane
+        let curvature = plane.regulators().with_untracked(
+            |regs| regs.first().unwrap().clone()
+        );
+        curvature.set_point().set(SpecifiedValue::try_from("0".to_string()).unwrap());
+    }
+    let all_perpendicular = [central.clone()].into_iter()
+        .chain(sides.clone())
+        .chain(corners.clone());
+    for sphere in all_perpendicular {
+        // make each side and packed sphere perpendicular to the assembly plane
+        let right_angle = InversiveDistanceRegulator::new([sphere, assemb_plane.clone()]);
+        right_angle.set_point.set(SpecifiedValue::try_from("0".to_string()).unwrap());
+        assembly.insert_regulator(Rc::new(right_angle));
+    }
+    for sphere in sides.clone().chain(corners.clone()) {
+        // make each side and corner sphere tangent to the central sphere
+        let tangency = InversiveDistanceRegulator::new([sphere.clone(), central.clone()]);
+        tangency.set_point.set(SpecifiedValue::try_from("-1".to_string()).unwrap());
+        assembly.insert_regulator(Rc::new(tangency));
+    }
+    for (side_index, side) in sides.enumerate() {
+        // make each side tangent to the two adjacent corner spheres
+        for (corner_index, corner) in corners.clone().enumerate() {
+            if side_index != corner_index {
+                let tangency = InversiveDistanceRegulator::new([side.clone(), corner]);
+                tangency.set_point.set(SpecifiedValue::try_from("-1".to_string()).unwrap());
+                assembly.insert_regulator(Rc::new(tangency));
+            }
+        }
+    }
+}
+
+fn load_pointed(assembly: &Assembly) {
+    let _ = assembly.try_insert_element(
+        Point::new(
+            format!("point_front"),
+            format!("Front point"),
+            [0.75_f32, 0.75_f32, 0.75_f32],
+            engine::point(0.0, 0.0, FRAC_1_SQRT_2),
+        )
+    );
+    let _ = assembly.try_insert_element(
+        Point::new(
+            format!("point_back"),
+            format!("Back point"),
+            [0.75_f32, 0.75_f32, 0.75_f32],
+            engine::point(0.0, 0.0, -FRAC_1_SQRT_2),
+        )
+    );
+    for index_x in 0..=1 {
+        for index_y in 0..=1 {
+            let x = index_x as f64 - 0.5;
+            let y = index_y as f64 - 0.5;
+            
+            let _ = assembly.try_insert_element(
+                Sphere::new(
+                    format!("sphere{index_x}{index_y}"),
+                    format!("Sphere {index_x}{index_y}"),
+                    [0.5*(1.0 + x) as f32, 0.5*(1.0 + y) as f32, 0.5*(1.0 - x*y) as f32],
+                    engine::sphere(x, y, 0.0, 1.0),
+                )
+            );
+            
+            let _ = assembly.try_insert_element(
+                Point::new(
+                    format!("point{index_x}{index_y}"),
+                    format!("Point {index_x}{index_y}"),
+                    [0.5*(1.0 + x) as f32, 0.5*(1.0 + y) as f32, 0.5*(1.0 - x*y) as f32],
+                    engine::point(x, y, 0.0),
+                )
+            );
+        }
+    }
+}
+
+// to finish describing the tridiminished icosahedron, set the inversive
+// distance regulators as follows:
+//   A-A   -0.25
+//   A-B     "
+//   B-C     "
+//   C-C     "
+//   A-C   -0.25 * φ^2 = -0.6545084971874737
+fn load_tridiminished_icosahedron(assembly: &Assembly) {
+    // create the vertices
+    const COLOR_A: ElementColor = [1.00_f32, 0.25_f32, 0.25_f32];
+    const COLOR_B: ElementColor = [0.75_f32, 0.75_f32, 0.75_f32];
+    const COLOR_C: ElementColor = [0.25_f32, 0.50_f32, 1.00_f32];
+    let vertices = [
+        Point::new(
+            "a1".to_string(),
+            "A₁".to_string(),
+            COLOR_A,
+            engine::point(0.25, 0.75, 0.75),
+        ),
+        Point::new(
+            "a2".to_string(),
+            "A₂".to_string(),
+            COLOR_A,
+            engine::point(0.75, 0.25, 0.75),
+        ),
+        Point::new(
+            "a3".to_string(),
+            "A₃".to_string(),
+            COLOR_A,
+            engine::point(0.75, 0.75, 0.25),
+        ),
+        Point::new(
+            "b1".to_string(),
+            "B₁".to_string(),
+            COLOR_B,
+            engine::point(0.75, -0.25, -0.25),
+        ),
+        Point::new(
+            "b2".to_string(),
+            "B₂".to_string(),
+            COLOR_B,
+            engine::point(-0.25, 0.75, -0.25),
+        ),
+        Point::new(
+            "b3".to_string(),
+            "B₃".to_string(),
+            COLOR_B,
+            engine::point(-0.25, -0.25, 0.75),
+        ),
+        Point::new(
+            "c1".to_string(),
+            "C₁".to_string(),
+            COLOR_C,
+            engine::point(0.0, -1.0, -1.0),
+        ),
+        Point::new(
+            "c2".to_string(),
+            "C₂".to_string(),
+            COLOR_C,
+            engine::point(-1.0, 0.0, -1.0),
+        ),
+        Point::new(
+            "c3".to_string(),
+            "C₃".to_string(),
+            COLOR_C,
+            engine::point(-1.0, -1.0, 0.0),
+        ),
+    ];
+    for vertex in vertices {
+        let _ = assembly.try_insert_element(vertex);
+    }
+    
+    // create the faces
+    const COLOR_FACE: ElementColor = [0.75_f32, 0.75_f32, 0.75_f32];
+    let frac_1_sqrt_6 = 1.0 / 6.0_f64.sqrt();
+    let frac_2_sqrt_6 = 2.0 * frac_1_sqrt_6;
+    let faces = [
+        Sphere::new(
+            "face1".to_string(),
+            "Face 1".to_string(),
+            COLOR_FACE,
+            engine::sphere_with_offset(frac_2_sqrt_6, -frac_1_sqrt_6, -frac_1_sqrt_6, -frac_1_sqrt_6, 0.0),
+        ),
+        Sphere::new(
+            "face2".to_string(),
+            "Face 2".to_string(),
+            COLOR_FACE,
+            engine::sphere_with_offset(-frac_1_sqrt_6, frac_2_sqrt_6, -frac_1_sqrt_6, -frac_1_sqrt_6, 0.0),
+        ),
+        Sphere::new(
+            "face3".to_string(),
+            "Face 3".to_string(),
+            COLOR_FACE,
+            engine::sphere_with_offset(-frac_1_sqrt_6, -frac_1_sqrt_6, frac_2_sqrt_6, -frac_1_sqrt_6, 0.0),
+        ),
+    ];
+    for face in faces {
+        face.ghost().set(true);
+        let _ = assembly.try_insert_element(face);
+    }
+    
+    let index_range = 1..=3;
+    for j in index_range.clone() {
+        // make each face planar
+        let face = assembly.elements_by_id.with_untracked(
+            |elts_by_id| elts_by_id[&format!("face{j}")].clone()
+        );
+        let curvature_regulator = face.regulators().with_untracked(
+            |regs| regs.first().unwrap().clone()
+        );
+        curvature_regulator.set_point().set(
+            SpecifiedValue::try_from("0".to_string()).unwrap()
+        );
+        
+        // put each A vertex on the face it belongs to
+        let vertex_a = assembly.elements_by_id.with_untracked(
+            |elts_by_id| elts_by_id[&format!("a{j}")].clone()
+        );
+        let incidence_a = InversiveDistanceRegulator::new([face.clone(), vertex_a.clone()]);
+        incidence_a.set_point.set(SpecifiedValue::try_from("0".to_string()).unwrap());
+        assembly.insert_regulator(Rc::new(incidence_a));
+        
+        // regulate the B-C vertex distances
+        let vertices_bc = ["b", "c"].map(
+            |series| assembly.elements_by_id.with_untracked(
+                |elts_by_id| elts_by_id[&format!("{series}{j}")].clone()
+            )
+        );
+        assembly.insert_regulator(
+            Rc::new(InversiveDistanceRegulator::new(vertices_bc))
+        );
+        
+        // get the pair of indices adjacent to `j`
+        let adjacent_indices = [j % 3 + 1, (j + 1) % 3 + 1];
+        
+        for k in adjacent_indices.clone() {
+            for series in ["b", "c"] {
+                // put each B and C vertex on the faces it belongs to
+                let vertex = assembly.elements_by_id.with_untracked(
+                    |elts_by_id| elts_by_id[&format!("{series}{k}")].clone()
+                );
+                let incidence = InversiveDistanceRegulator::new([face.clone(), vertex.clone()]);
+                incidence.set_point.set(SpecifiedValue::try_from("0".to_string()).unwrap());
+                assembly.insert_regulator(Rc::new(incidence));
+                
+                // regulate the A-B and A-C vertex distances
+                assembly.insert_regulator(
+                    Rc::new(InversiveDistanceRegulator::new([vertex_a.clone(), vertex]))
+                );
+            }
+        }
+        
+        // regulate the A-A and C-C vertex distances
+        let adjacent_pairs = ["a", "c"].map(
+            |series| adjacent_indices.map(
+                |index| assembly.elements_by_id.with_untracked(
+                    |elts_by_id| elts_by_id[&format!("{series}{index}")].clone()
+                )
+            )
+        );
+        for pair in adjacent_pairs {
+            assembly.insert_regulator(
+                Rc::new(InversiveDistanceRegulator::new(pair))
+            );
+        }
+    }
+}
+
+// to finish describing the dodecahedral circle packing, set the inversive
+// distance regulators to -1. some of the regulators have already been set
+fn load_dodecahedral_packing(assembly: &Assembly) {
+    // add the substrate
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            "substrate".to_string(),
+            "Substrate".to_string(),
+            [0.75_f32, 0.75_f32, 0.75_f32],
+            engine::sphere(0.0, 0.0, 0.0, 1.0),
+        )
+    );
+    let substrate = assembly.elements_by_id.with_untracked(
+        |elts_by_id| elts_by_id["substrate"].clone()
+    );
+    
+    // fix the substrate's curvature
+    substrate.regulators().with_untracked(
+        |regs| regs.first().unwrap().clone()
+    ).set_point().set(
+        SpecifiedValue::try_from("0.5".to_string()).unwrap()
+    );
+    
+    // add the circles to be packed
+    const COLOR_A: ElementColor = [1.00_f32, 0.25_f32, 0.00_f32];
+    const COLOR_B: ElementColor = [1.00_f32, 0.00_f32, 0.25_f32];
+    const COLOR_C: ElementColor = [0.25_f32, 0.00_f32, 1.00_f32];
+    let phi = 0.5 + 1.25_f64.sqrt(); /* TO DO */ // replace with std::f64::consts::PHI when that gets stabilized
+    let phi_inv = 1.0 / phi;
+    let coord_scale = (phi + 2.0).sqrt();
+    let face_scales = [phi_inv, (13.0 / 12.0) / coord_scale];
+    let face_radii = [phi_inv, 5.0 / 12.0];
+    let mut faces = Vec::<Rc<dyn Element>>::new();
+    let subscripts = ["₀", "₁"];
+    for j in 0..2 {
+        for k in 0..2 {
+            let small_coord = face_scales[k] * (2.0*(j as f64) - 1.0);
+            let big_coord = face_scales[k] * (2.0*(k as f64) - 1.0) * phi;
+            
+            let id_num = format!("{j}{k}");
+            let label_sub = format!("{}{}", subscripts[j], subscripts[k]);
+            
+            // add the A face
+            let id_a = format!("a{id_num}");
+            let _ = assembly.try_insert_element(
+                Sphere::new(
+                    id_a.clone(),
+                    format!("A{label_sub}"),
+                    COLOR_A,
+                    engine::sphere(0.0, small_coord, big_coord, face_radii[k]),
+                )
+            );
+            faces.push(
+                assembly.elements_by_id.with_untracked(
+                    |elts_by_id| elts_by_id[&id_a].clone()
+                )
+            );
+            
+            // add the B face
+            let id_b = format!("b{id_num}");
+            let _ = assembly.try_insert_element(
+                Sphere::new(
+                    id_b.clone(),
+                    format!("B{label_sub}"),
+                    COLOR_B,
+                    engine::sphere(small_coord, big_coord, 0.0, face_radii[k]),
+                )
+            );
+            faces.push(
+                assembly.elements_by_id.with_untracked(
+                    |elts_by_id| elts_by_id[&id_b].clone()
+                )
+            );
+            
+            // add the C face
+            let id_c = format!("c{id_num}");
+            let _ = assembly.try_insert_element(
+                Sphere::new(
+                    id_c.clone(),
+                    format!("C{label_sub}"),
+                    COLOR_C,
+                    engine::sphere(big_coord, 0.0, small_coord, face_radii[k]),
+                )
+            );
+            faces.push(
+                assembly.elements_by_id.with_untracked(
+                    |elts_by_id| elts_by_id[&id_c].clone()
+                )
+            );
+        }
+    }
+    
+    // make each face sphere perpendicular to the substrate
+    for face in faces {
+        let right_angle = InversiveDistanceRegulator::new([face, substrate.clone()]);
+        right_angle.set_point.set(SpecifiedValue::try_from("0".to_string()).unwrap());
+        assembly.insert_regulator(Rc::new(right_angle));
+    }
+    
+    // set up the tangencies that define the packing
+    for [long_edge_plane, short_edge_plane] in [["a", "b"], ["b", "c"], ["c", "a"]] {
+        for k in 0..2 {
+            let long_edge_ids = [
+                format!("{long_edge_plane}{k}0"),
+                format!("{long_edge_plane}{k}1")
+            ];
+            let short_edge_ids = [
+                format!("{short_edge_plane}0{k}"),
+                format!("{short_edge_plane}1{k}")
+            ];
+            let [long_edge, short_edge] = [long_edge_ids, short_edge_ids].map(
+                |edge_ids| edge_ids.map(
+                    |id| assembly.elements_by_id.with_untracked(
+                        |elts_by_id| elts_by_id[&id].clone()
+                    )
+                )
+            );
+            
+            // set up the short-edge tangency
+            let short_tangency = InversiveDistanceRegulator::new(short_edge.clone());
+            if k == 0 {
+                short_tangency.set_point.set(SpecifiedValue::try_from("-1".to_string()).unwrap());
+            }
+            assembly.insert_regulator(Rc::new(short_tangency));
+            
+            // set up the side tangencies
+            for i in 0..2 {
+                for j in 0..2 {
+                    let side_tangency = InversiveDistanceRegulator::new(
+                        [long_edge[i].clone(), short_edge[j].clone()]
+                    );
+                    if i == 0 && k == 0 {
+                        side_tangency.set_point.set(SpecifiedValue::try_from("-1".to_string()).unwrap());
+                    }
+                    assembly.insert_regulator(Rc::new(side_tangency));
+                }
+            }
+        }
+    }
+}
+
+// the initial configuration of this test assembly deliberately violates the
+// constraints, so loading the assembly will trigger a non-trivial realization
+fn load_balanced(assembly: &Assembly) {
+    // create the spheres
+    const R_OUTER: f64 = 10.0;
+    const R_INNER: f64 = 4.0;
+    let spheres = [
+        Sphere::new(
+            "outer".to_string(),
+            "Outer".to_string(),
+            [0.75_f32, 0.75_f32, 0.75_f32],
+            engine::sphere(0.0, 0.0, 0.0, R_OUTER),
+        ),
+        Sphere::new(
+            "a".to_string(),
+            "A".to_string(),
+            [1.00_f32, 0.00_f32, 0.25_f32],
+            engine::sphere(0.0, 4.0, 0.0, R_INNER),
+        ),
+        Sphere::new(
+            "b".to_string(),
+            "B".to_string(),
+            [0.00_f32, 0.25_f32, 1.00_f32],
+            engine::sphere(0.0, -4.0, 0.0, R_INNER),
+        ),
+    ];
+    for sphere in spheres {
+        let _ = assembly.try_insert_element(sphere);
+    }
+    
+    // get references to the spheres
+    let [outer, a, b] = ["outer", "a", "b"].map(
+        |id| assembly.elements_by_id.with_untracked(
+            |elts_by_id| elts_by_id[id].clone()
+        )
+    );
+    
+    // fix the diameters of the outer, sun, and moon spheres
+    for (sphere, radius) in [
+        (outer.clone(), R_OUTER),
+        (a.clone(), R_INNER),
+        (b.clone(), R_INNER),
+    ] {
+        let curvature_regulator = sphere.regulators().with_untracked(
+            |regs| regs.first().unwrap().clone()
+        );
+        let curvature = 0.5 / radius;
+        curvature_regulator.set_point().set(
+            SpecifiedValue::try_from(curvature.to_string()).unwrap()
+        );
+    }
+    
+    // set the inversive distances between the spheres. as described above, the
+    // initial configuration deliberately violates these constraints
+    for inner in [a, b] {
+        let tangency = InversiveDistanceRegulator::new([outer.clone(), inner]);
+        tangency.set_point.set(SpecifiedValue::try_from("1".to_string()).unwrap());
+        assembly.insert_regulator(Rc::new(tangency));
+    }
+}
+
+// the initial configuration of this test assembly deliberately violates the
+// constraints, so loading the assembly will trigger a non-trivial realization
+fn load_off_center(assembly: &Assembly) {
+    // create a point almost at the origin and a sphere centered on the origin
+    let _ = assembly.try_insert_element(
+        Point::new(
+            "point".to_string(),
+            "Point".to_string(),
+            [0.75_f32, 0.75_f32, 0.75_f32],
+            engine::point(1e-9, 0.0, 0.0),
+        ),
+    );
+    let _ = assembly.try_insert_element(
+        Sphere::new(
+            "sphere".to_string(),
+            "Sphere".to_string(),
+            [0.75_f32, 0.75_f32, 0.75_f32],
+            engine::sphere(0.0, 0.0, 0.0, 1.0),
+        ),
+    );
+    
+    // get references to the elements
+    let point_and_sphere = ["point", "sphere"].map(
+        |id| assembly.elements_by_id.with_untracked(
+            |elts_by_id| elts_by_id[id].clone()
+        )
+    );
+    
+    // put the point on the sphere
+    let incidence = InversiveDistanceRegulator::new(point_and_sphere);
+    incidence.set_point.set(SpecifiedValue::try_from("0".to_string()).unwrap());
+    assembly.insert_regulator(Rc::new(incidence));
+}
+
+// setting the inversive distances between the vertices to -2 gives a regular
+// tetrahedron with side length 1, whose insphere and circumsphere have radii
+// sqrt(1/6) and sqrt(3/2), respectively. to measure those radii, set an
+// inversive distance of -1 between the insphere and each face, and then set an
+// inversive distance of 0 between the circumsphere and each vertex
+fn load_radius_ratio(assembly: &Assembly) {
+    let index_range = 1..=4;
+    
+    // create the spheres
+    const GRAY: ElementColor = [0.75_f32, 0.75_f32, 0.75_f32];
+    let spheres = [
+        Sphere::new(
+            "sphere_faces".to_string(),
+            "Insphere".to_string(),
+            GRAY,
+            engine::sphere(0.0, 0.0, 0.0, 0.5),
+        ),
+        Sphere::new(
+            "sphere_vertices".to_string(),
+            "Circumsphere".to_string(),
+            GRAY,
+            engine::sphere(0.0, 0.0, 0.0, 0.25),
+        ),
+    ];
+    for sphere in spheres {
+        let _ = assembly.try_insert_element(sphere);
+    }
+    
+    // create the vertices
+    let vertices = izip!(
+        index_range.clone(),
+        [
+            [1.00_f32, 0.50_f32, 0.75_f32],
+            [1.00_f32, 0.75_f32, 0.50_f32],
+            [1.00_f32, 1.00_f32, 0.50_f32],
+            [0.75_f32, 0.50_f32, 1.00_f32],
+        ].into_iter(),
+        [
+            engine::point(-0.6, -0.8, -0.6),
+            engine::point(-0.6, 0.8, 0.6),
+            engine::point(0.6, -0.8, 0.6),
+            engine::point(0.6, 0.8, -0.6),
+        ].into_iter()
+    ).map(
+        |(k, color, representation)| {
+            Point::new(
+                format!("v{k}"),
+                format!("Vertex {k}"),
+                color,
+                representation,
+            )
+        }
+    );
+    for vertex in vertices {
+        let _ = assembly.try_insert_element(vertex);
+    }
+    
+    // create the faces
+    let base_dir = Vector3::new(1.0, 0.75, 1.0).normalize();
+    let offset = base_dir.dot(&Vector3::new(-0.6, 0.8, 0.6));
+    let faces = izip!(
+        index_range.clone(),
+        [
+            [1.00_f32, 0.00_f32, 0.25_f32],
+            [1.00_f32, 0.25_f32, 0.00_f32],
+            [0.75_f32, 0.75_f32, 0.00_f32],
+            [0.25_f32, 0.00_f32, 1.00_f32],
+        ].into_iter(),
+        [
+            engine::sphere_with_offset(base_dir[0], base_dir[1], base_dir[2], offset, 0.0),
+            engine::sphere_with_offset(base_dir[0], -base_dir[1], -base_dir[2], offset, 0.0),
+            engine::sphere_with_offset(-base_dir[0], base_dir[1], -base_dir[2], offset, 0.0),
+            engine::sphere_with_offset(-base_dir[0], -base_dir[1], base_dir[2], offset, 0.0),
+        ].into_iter()
+    ).map(
+        |(k, color, representation)| {
+            Sphere::new(
+                format!("f{k}"),
+                format!("Face {k}"),
+                color,
+                representation,
+            )
+        }
+    );
+    for face in faces {
+        face.ghost().set(true);
+        let _ = assembly.try_insert_element(face);
+    }
+    
+    // impose the constraints
+    for j in index_range.clone() {
+        let [face_j, vertex_j] = [
+            format!("f{j}"),
+            format!("v{j}"),
+        ].map(
+            |id| assembly.elements_by_id.with_untracked(
+                |elts_by_id| elts_by_id[&id].clone()
+            )
+        );
+        
+        // make the faces planar
+        let curvature_regulator = face_j.regulators().with_untracked(
+            |regs| regs.first().unwrap().clone()
+        );
+        curvature_regulator.set_point().set(
+            SpecifiedValue::try_from("0".to_string()).unwrap()
+        );
+        
+        for k in index_range.clone().filter(|&index| index != j) {
+            let vertex_k = assembly.elements_by_id.with_untracked(
+                |elts_by_id| elts_by_id[&format!("v{k}")].clone()
+            );
+            
+            // fix the distances between the vertices
+            if j < k {
+                let distance_regulator = InversiveDistanceRegulator::new(
+                    [vertex_j.clone(), vertex_k.clone()]
+                );
+                assembly.insert_regulator(Rc::new(distance_regulator));
+            }
+            
+            // put the vertices on the faces
+            let incidence_regulator = InversiveDistanceRegulator::new([face_j.clone(), vertex_k.clone()]);
+            incidence_regulator.set_point.set(SpecifiedValue::try_from("0".to_string()).unwrap());
+            assembly.insert_regulator(Rc::new(incidence_regulator));
+        }
+    }
+}
+
+// to finish setting up the problem, fix the following curvatures:
+//   sun      1
+//   moon     5/3 = 1.666666666666666...
+//   chain1   2
+// a tiny `x` or `z` nudge of the outer sphere reliably prevents realization
+// failures before they happen, or resolves them after they happen. the result
+// depends sensitively on the translation direction, suggesting that realization
+// is failing because the engine is having trouble breaking a symmetry
+// /* TO DO */
+// the engine's performance on this problem is scale-dependent! with the current
+// initial conditions, realization fails for any order of imposing the remaining
+// curvature constraints. scaling everything up by a factor of ten, as done in
+// the original problem, makes realization succeed reliably. one potentially
+// relevant difference is that a lot of the numbers in the current initial
+// conditions are exactly representable as floats, unlike the analogous numbers
+// in the scaled-up problem. the inexact representations might break the
+// symmetry that's getting the engine stuck
+fn load_irisawa_hexlet(assembly: &Assembly) {
+    let index_range = 1..=6;
+    let colors = [
+        [1.00_f32, 0.00_f32, 0.25_f32],
+        [1.00_f32, 0.25_f32, 0.00_f32],
+        [0.75_f32, 0.75_f32, 0.00_f32],
+        [0.25_f32, 1.00_f32, 0.00_f32],
+        [0.00_f32, 0.25_f32, 1.00_f32],
+        [0.25_f32, 0.00_f32, 1.00_f32],
+    ].into_iter();
+    
+    // create the spheres
+    let spheres = [
+        Sphere::new(
+            "outer".to_string(),
+            "Outer".to_string(),
+            [0.5_f32, 0.5_f32, 0.5_f32],
+            engine::sphere(0.0, 0.0, 0.0, 1.5),
+        ),
+        Sphere::new(
+            "sun".to_string(),
+            "Sun".to_string(),
+            [0.75_f32, 0.75_f32, 0.75_f32],
+            engine::sphere(0.0, -0.75, 0.0, 0.75),
+        ),
+        Sphere::new(
+            "moon".to_string(),
+            "Moon".to_string(),
+            [0.25_f32, 0.25_f32, 0.25_f32],
+            engine::sphere(0.0, 0.75, 0.0, 0.75),
+        ),
+    ].into_iter().chain(
+        index_range.clone().zip(colors).map(
+            |(k, color)| {
+                let ang = (k as f64) * PI/3.0;
+                Sphere::new(
+                    format!("chain{k}"),
+                    format!("Chain {k}"),
+                    color,
+                    engine::sphere(1.0 * ang.sin(), 0.0, 1.0 * ang.cos(), 0.5),
+                )
+            }
+        )
+    );
+    for sphere in spheres {
+        let _ = assembly.try_insert_element(sphere);
+    }
+    
+    // put the outer sphere in ghost mode and fix its curvature
+    let outer = assembly.elements_by_id.with_untracked(
+        |elts_by_id| elts_by_id["outer"].clone()
+    );
+    outer.ghost().set(true);
+    let outer_curvature_regulator = outer.regulators().with_untracked(
+        |regs| regs.first().unwrap().clone()
+    );
+    outer_curvature_regulator.set_point().set(
+        SpecifiedValue::try_from((1.0 / 3.0).to_string()).unwrap()
+    );
+    
+    // impose the desired tangencies
+    let [outer, sun, moon] = ["outer", "sun", "moon"].map(
+        |id| assembly.elements_by_id.with_untracked(
+            |elts_by_id| elts_by_id[id].clone()
+        )
+    );
+    let chain = index_range.map(
+        |k| assembly.elements_by_id.with_untracked(
+            |elts_by_id| elts_by_id[&format!("chain{k}")].clone()
+        )
+    );
+    for (chain_sphere, chain_sphere_next) in chain.clone().zip(chain.cycle().skip(1)) {
+        for (other_sphere, inversive_distance) in [
+            (outer.clone(), "1"),
+            (sun.clone(), "-1"),
+            (moon.clone(), "-1"),
+            (chain_sphere_next.clone(), "-1"),
+        ] {
+            let tangency = InversiveDistanceRegulator::new([chain_sphere.clone(), other_sphere]);
+            tangency.set_point.set(SpecifiedValue::try_from(inversive_distance.to_string()).unwrap());
+            assembly.insert_regulator(Rc::new(tangency));
+        }
+    }
+    
+    let outer_sun_tangency = InversiveDistanceRegulator::new([outer.clone(), sun]);
+    outer_sun_tangency.set_point.set(SpecifiedValue::try_from("1".to_string()).unwrap());
+    assembly.insert_regulator(Rc::new(outer_sun_tangency));
+    
+    let outer_moon_tangency = InversiveDistanceRegulator::new([outer.clone(), moon]);
+    outer_moon_tangency.set_point.set(SpecifiedValue::try_from("1".to_string()).unwrap());
+    assembly.insert_regulator(Rc::new(outer_moon_tangency));
+}
+
+// --- chooser ---
+
+/* DEBUG */
+#[component]
+pub fn TestAssemblyChooser() -> View {
+    // create an effect that loads the selected test assembly
+    let assembly_name = create_signal("general".to_string());
+    create_effect(move || {
+        // get name of chosen assembly
+        let name = assembly_name.get_clone();
+        console::log_1(
+            &JsValue::from(format!("Showing assembly \"{}\"", name.clone()))
+        );
+        
+        batch(|| {
+            let state = use_context::<AppState>();
+            let assembly = &state.assembly;
+            
+            // clear state
+            assembly.regulators.update(|regs| regs.clear());
+            assembly.elements.update(|elts| elts.clear());
+            assembly.elements_by_id.update(|elts_by_id| elts_by_id.clear());
+            assembly.descent_history.set(DescentHistory::new());
+            state.selection.update(|sel| sel.clear());
+            
+            // load assembly
+            match name.as_str() {
+                "general" => load_general(assembly),
+                "low-curvature" => load_low_curvature(assembly),
+                "pointed" => load_pointed(assembly),
+                "tridiminished-icosahedron" => load_tridiminished_icosahedron(assembly),
+                "dodecahedral-packing" => load_dodecahedral_packing(assembly),
+                "balanced" => load_balanced(assembly),
+                "off-center" => load_off_center(assembly),
+                "radius-ratio" => load_radius_ratio(assembly),
+                "irisawa-hexlet" => load_irisawa_hexlet(assembly),
+                _ => (),
+            };
+        });
+    });
+    
+    // build the chooser
+    view! {
+        select(bind:value = assembly_name) {
+            option(value = "general") { "General" }
+            option(value = "low-curvature") { "Low-curvature" }
+            option(value = "pointed") { "Pointed" }
+            option(value = "tridiminished-icosahedron") { "Tridiminished icosahedron" }
+            option(value = "dodecahedral-packing") { "Dodecahedral packing" }
+            option(value = "balanced") { "Balanced" }
+            option(value = "off-center") { "Off-center" }
+            option(value = "radius-ratio") { "Radius ratio" }
+            option(value = "irisawa-hexlet") { "Irisawa hexlet" }
+            option(value = "empty") { "Empty" }
+        }
+    }
+}
\ No newline at end of file
diff --git a/app-proto/src/engine.rs b/app-proto/src/engine.rs
index e6ffa25..d033c01 100644
--- a/app-proto/src/engine.rs
+++ b/app-proto/src/engine.rs
@@ -1,7 +1,6 @@
 use lazy_static::lazy_static;
 use nalgebra::{Const, DMatrix, DVector, DVectorView, Dyn, SymmetricEigen};
 use std::fmt::{Display, Error, Formatter};
-use web_sys::{console, wasm_bindgen::JsValue}; /* DEBUG */
 
 // --- elements ---
 
@@ -17,7 +16,7 @@ pub fn sphere(center_x: f64, center_y: f64, center_z: f64, radius: f64) -> DVect
         center_y / radius,
         center_z / radius,
         0.5 / radius,
-        0.5 * (center_norm_sq / radius - radius)
+        0.5 * (center_norm_sq / radius - radius),
     ])
 }
 
@@ -31,7 +30,7 @@ pub fn sphere_with_offset(dir_x: f64, dir_y: f64, dir_z: f64, off: f64, curv: f6
         norm_sp * dir_y,
         norm_sp * dir_z,
         0.5 * curv,
-        off * (1.0 + 0.5 * off * curv)
+        off * (1.0 + 0.5 * off * curv),
     ])
 }
 
@@ -50,57 +49,23 @@ pub fn project_point_to_normalized(rep: &mut DVector<f64>) {
     rep.scale_mut(0.5 / rep[3]);
 }
 
-// given a sphere's representation vector, change the sphere's half-curvature to
-// `half-curv` and then restore normalization by contracting the representation
-// vector toward the curvature axis
-pub fn change_half_curvature(rep: &mut DVector<f64>, half_curv: f64) {
-    // set the sphere's half-curvature to the desired value
-    rep[3] = half_curv;
-    
-    // restore normalization by contracting toward the curvature axis
-    const SIZE_THRESHOLD: f64 = 1e-9;
-    let half_q_lt = -2.0 * half_curv * rep[4];
-    let half_q_lt_sq = half_q_lt * half_q_lt;
-    let mut spatial = rep.fixed_rows_mut::<3>(0);
-    let q_sp = spatial.norm_squared();
-    if q_sp < SIZE_THRESHOLD && half_q_lt_sq < SIZE_THRESHOLD {
-        spatial.copy_from_slice(
-            &[0.0, 0.0, (1.0 - 2.0 * half_q_lt).sqrt()]
-        );
-    } else {
-        let scaling = half_q_lt + (q_sp + half_q_lt_sq).sqrt();
-        spatial.scale_mut(1.0 / scaling);
-        rep[4] /= scaling;
-    }
-    
-    /* DEBUG */
-    // verify normalization
-    let rep_for_debug = rep.clone();
-    console::log_1(&JsValue::from(
-        format!(
-            "Sphere self-product after curvature change: {}",
-            rep_for_debug.dot(&(&*Q * &rep_for_debug))
-        )
-    ));
-}
-
 // --- partial matrices ---
 
 pub struct MatrixEntry {
     index: (usize, usize),
-    value: f64
+    value: f64,
 }
 
 pub struct PartialMatrix(Vec<MatrixEntry>);
 
 impl PartialMatrix {
-    pub fn new() -> PartialMatrix {
-        PartialMatrix(Vec::<MatrixEntry>::new())
+    pub fn new() -> Self {
+        Self(Vec::<MatrixEntry>::new())
     }
     
     pub fn push(&mut self, row: usize, col: usize, value: f64) {
-        let PartialMatrix(entries) = self;
-        entries.push(MatrixEntry { index: (row, col), value: value });
+        let Self(entries) = self;
+        entries.push(MatrixEntry { index: (row, col), value });
     }
     
     pub fn push_sym(&mut self, row: usize, col: usize, value: f64) {
@@ -149,7 +114,7 @@ impl IntoIterator for PartialMatrix {
     type IntoIter = std::vec::IntoIter<Self::Item>;
     
     fn into_iter(self) -> Self::IntoIter {
-        let PartialMatrix(entries) = self;
+        let Self(entries) = self;
         entries.into_iter()
     }
 }
@@ -170,22 +135,26 @@ impl<'a> IntoIterator for &'a PartialMatrix {
 pub struct ConfigSubspace {
     assembly_dim: usize,
     basis_std: Vec<DMatrix<f64>>,
-    basis_proj: Vec<DMatrix<f64>>
+    basis_proj: Vec<DMatrix<f64>>,
 }
 
 impl ConfigSubspace {
-    pub fn zero(assembly_dim: usize) -> ConfigSubspace {
-        ConfigSubspace {
-            assembly_dim: assembly_dim,
+    pub fn zero(assembly_dim: usize) -> Self {
+        Self {
+            assembly_dim,
             basis_proj: Vec::new(),
-            basis_std: Vec::new()
+            basis_std: Vec::new(),
         }
     }
     
     // approximate the kernel of a symmetric endomorphism of the configuration
     // space for `assembly_dim` elements. we consider an eigenvector to be part
     // of the kernel if its eigenvalue is smaller than the constant `THRESHOLD`
-    fn symmetric_kernel(a: DMatrix<f64>, proj_to_std: DMatrix<f64>, assembly_dim: usize) -> ConfigSubspace {
+    fn symmetric_kernel(
+        a: DMatrix<f64>,
+        proj_to_std: DMatrix<f64>,
+        assembly_dim: usize,
+    ) -> Self {
         // find a basis for the kernel. the basis is expressed in the projection
         // coordinates, and it's orthonormal with respect to the projection
         // inner product
@@ -199,20 +168,13 @@ impl ConfigSubspace {
             ).collect::<Vec<_>>().as_slice()
         );
         
-        /* DEBUG */
-        // print the eigenvalues
-        #[cfg(all(target_family = "wasm", target_os = "unknown"))]
-        console::log_1(&JsValue::from(
-            format!("Eigenvalues used to find kernel:{}", eig.eigenvalues)
-        ));
-        
         // express the basis in the standard coordinates
         let basis_std = proj_to_std * &basis_proj;
         
         const ELEMENT_DIM: usize = 5;
         const UNIFORM_DIM: usize = 4;
-        ConfigSubspace {
-            assembly_dim: assembly_dim,
+        Self {
+            assembly_dim,
             basis_std: basis_std.column_iter().map(
                 |v| Into::<DMatrix<f64>>::into(
                     v.reshape_generic(Dyn(ELEMENT_DIM), Dyn(assembly_dim))
@@ -222,7 +184,7 @@ impl ConfigSubspace {
                 |v| Into::<DMatrix<f64>>::into(
                     v.reshape_generic(Dyn(UNIFORM_DIM), Dyn(assembly_dim))
                 )
-            ).collect()
+            ).collect(),
         }
     }
     
@@ -256,14 +218,14 @@ pub struct DescentHistory {
     pub config: Vec<DMatrix<f64>>,
     pub scaled_loss: Vec<f64>,
     pub neg_grad: Vec<DMatrix<f64>>,
-    pub hess_eigvals: Vec::<DVector<f64>>,
+    pub hess_eigvals: Vec<DVector<f64>>,
     pub base_step: Vec<DMatrix<f64>>,
-    pub backoff_steps: Vec<i32>
+    pub backoff_steps: Vec<i32>,
 }
 
 impl DescentHistory {
-    pub fn new() -> DescentHistory {
-        DescentHistory {
+    pub fn new() -> Self {
+        Self {
             config: Vec::<DMatrix<f64>>::new(),
             scaled_loss: Vec::<f64>::new(),
             neg_grad: Vec::<DMatrix<f64>>::new(),
@@ -283,21 +245,21 @@ pub struct ConstraintProblem {
 }
 
 impl ConstraintProblem {
-    pub fn new(element_count: usize) -> ConstraintProblem {
+    pub fn new(element_count: usize) -> Self {
         const ELEMENT_DIM: usize = 5;
-        ConstraintProblem {
+        Self {
             gram: PartialMatrix::new(),
             frozen: PartialMatrix::new(),
-            guess: DMatrix::<f64>::zeros(ELEMENT_DIM, element_count)
+            guess: DMatrix::<f64>::zeros(ELEMENT_DIM, element_count),
         }
     }
     
     #[cfg(feature = "dev")]
-    pub fn from_guess(guess_columns: &[DVector<f64>]) -> ConstraintProblem {
-        ConstraintProblem {
+    pub fn from_guess(guess_columns: &[DVector<f64>]) -> Self {
+        Self {
             gram: PartialMatrix::new(),
             frozen: PartialMatrix::new(),
-            guess: DMatrix::from_columns(guess_columns)
+            guess: DMatrix::from_columns(guess_columns),
         }
     }
 }
@@ -311,25 +273,21 @@ lazy_static! {
         0.0, 1.0, 0.0,  0.0,  0.0,
         0.0, 0.0, 1.0,  0.0,  0.0,
         0.0, 0.0, 0.0,  0.0, -2.0,
-        0.0, 0.0, 0.0, -2.0,  0.0
+        0.0, 0.0, 0.0, -2.0,  0.0,
     ]);
 }
 
 struct SearchState {
     config: DMatrix<f64>,
     err_proj: DMatrix<f64>,
-    loss: f64
+    loss: f64,
 }
 
 impl SearchState {
-    fn from_config(gram: &PartialMatrix, config: DMatrix<f64>) -> SearchState {
+    fn from_config(gram: &PartialMatrix, config: DMatrix<f64>) -> Self {
         let err_proj = gram.sub_proj(&(config.tr_mul(&*Q) * &config));
         let loss = err_proj.norm_squared();
-        SearchState {
-            config: config,
-            err_proj: err_proj,
-            loss: loss
-        }
+        Self { config, err_proj, loss }
     }
 }
 
@@ -356,7 +314,7 @@ pub fn local_unif_to_std(v: DVectorView<f64>) -> DMatrix<f64> {
             curv,  0.0,  0.0,  0.0, v[0],
              0.0, curv,  0.0,  0.0, v[1],
              0.0,  0.0, curv,  0.0, v[2],
-             0.0,  0.0,  0.0,  0.0,  1.0
+             0.0,  0.0,  0.0,  0.0,  1.0,
         ])
     } else {
         // `v` represents a sphere. the normalization condition says that the
@@ -365,7 +323,7 @@ pub fn local_unif_to_std(v: DVectorView<f64>) -> DMatrix<f64> {
                  curv,       0.0,       0.0,       0.0,            v[0],
                   0.0,      curv,       0.0,       0.0,            v[1],
                   0.0,       0.0,      curv,       0.0,            v[2],
-            curv*v[0], curv*v[1], curv*v[2], curv*v[3], curv*v[4] + 1.0
+            curv*v[0], curv*v[1], curv*v[2], curv*v[3], curv*v[4] + 1.0,
         ])
     }
 }
@@ -378,7 +336,7 @@ fn seek_better_config(
     base_target_improvement: f64,
     min_efficiency: f64,
     backoff: f64,
-    max_backoff_steps: i32
+    max_backoff_steps: i32,
 ) -> Option<(SearchState, i32)> {
     let mut rate = 1.0;
     for backoff_steps in 0..max_backoff_steps {
@@ -396,12 +354,12 @@ fn seek_better_config(
 // a first-order neighborhood of a configuration
 pub struct ConfigNeighborhood {
     pub config: DMatrix<f64>,
-    pub nbhd: ConfigSubspace
+    pub nbhd: ConfigSubspace,
 }
 
 pub struct Realization {
     pub result: Result<ConfigNeighborhood, String>,
-    pub history: DescentHistory
+    pub history: DescentHistory,
 }
 
 // seek a matrix `config` that matches the partial matrix `problem.frozen` and
@@ -415,19 +373,30 @@ pub fn realize_gram(
     backoff: f64,
     reg_scale: f64,
     max_descent_steps: i32,
-    max_backoff_steps: i32
+    max_backoff_steps: i32,
 ) -> Realization {
     // destructure the problem data
-    let ConstraintProblem {
-        gram, guess, frozen
-    } = problem;
+    let ConstraintProblem { gram, guess, frozen } = problem;
     
     // start the descent history
     let mut history = DescentHistory::new();
     
+    // handle the case where the assembly is empty. our general realization
+    // routine can't handle this case because it builds the Hessian using
+    // `DMatrix::from_columns`, which panics when the list of columns is empty
+    let assembly_dim = guess.ncols();
+    if assembly_dim == 0 {
+        let result = Ok(
+            ConfigNeighborhood {
+                config: guess.clone(),
+                nbhd: ConfigSubspace::zero(0),
+            }
+        );
+        return Realization { result, history };
+    }
+    
     // find the dimension of the search space
     let element_dim = guess.nrows();
-    let assembly_dim = guess.ncols();
     let total_dim = element_dim * assembly_dim;
     
     // scale the tolerance
@@ -504,8 +473,8 @@ pub fn realize_gram(
             Some(cholesky) => cholesky,
             None => return Realization {
                 result: Err("Cholesky decomposition failed".to_string()),
-                history
-            }
+                history,
+            },
         };
         let base_step_stacked = hess_cholesky.solve(&neg_grad_stacked);
         let base_step = base_step_stacked.reshape_generic(Dyn(element_dim), Dyn(assembly_dim));
@@ -514,16 +483,16 @@ pub fn realize_gram(
         // use backtracking line search to find a better configuration
         if let Some((better_state, backoff_steps)) = seek_better_config(
             gram, &state, &base_step, neg_grad.dot(&base_step),
-            min_efficiency, backoff, max_backoff_steps
+            min_efficiency, backoff, max_backoff_steps,
         ) {
             state = better_state;
             history.backoff_steps.push(backoff_steps);
         } else {
             return Realization {
                 result: Err("Line search failed".to_string()),
-                history
-            }
-        };
+                history,
+            };
+        }
     }
     let result = if state.loss < tol {
         // express the uniform basis in the standard basis
@@ -568,7 +537,7 @@ pub mod examples {
             [
                 sphere(0.0, 0.0, 0.0, 15.0),
                 sphere(0.0, 0.0, -9.0, 5.0),
-                sphere(0.0, 0.0, 11.0, 3.0)
+                sphere(0.0, 0.0, 11.0, 3.0),
             ].into_iter().chain(
                 (1..=6).map(
                     |k| {
@@ -627,7 +596,7 @@ pub mod examples {
                         point(0.0, 0.0, 0.0),
                         point(ang_hor.cos(), ang_hor.sin(), 0.0),
                         point(x_vert, y_vert, -0.5),
-                        point(x_vert, y_vert, 0.5)
+                        point(x_vert, y_vert, 0.5),
                     ]
                 }
             ).collect::<Vec<_>>().as_slice()
@@ -670,15 +639,15 @@ mod tests {
             MatrixEntry { index: (0, 0), value: 14.0 },
             MatrixEntry { index: (0, 2), value: 28.0 },
             MatrixEntry { index: (1, 1), value: 42.0 },
-            MatrixEntry { index: (1, 2), value: 49.0 }
+            MatrixEntry { index: (1, 2), value: 49.0 },
         ]);
         let config = DMatrix::<f64>::from_row_slice(2, 3, &[
             1.0, 2.0, 3.0,
-            4.0, 5.0, 6.0
+            4.0, 5.0, 6.0,
         ]);
         let expected_result = DMatrix::<f64>::from_row_slice(2, 3, &[
             14.0, 2.0, 28.0,
-            4.0, 42.0, 49.0
+            4.0, 42.0, 49.0,
         ]);
         assert_eq!(frozen.freeze(&config), expected_result);
     }
@@ -689,15 +658,15 @@ mod tests {
             MatrixEntry { index: (0, 0), value: 19.0 },
             MatrixEntry { index: (0, 2), value: 39.0 },
             MatrixEntry { index: (1, 1), value: 59.0 },
-            MatrixEntry { index: (1, 2), value: 69.0 }
+            MatrixEntry { index: (1, 2), value: 69.0 },
         ]);
         let attempt = DMatrix::<f64>::from_row_slice(2, 3, &[
             1.0, 2.0, 3.0,
-            4.0, 5.0, 6.0
+            4.0, 5.0, 6.0,
         ]);
         let expected_result = DMatrix::<f64>::from_row_slice(2, 3, &[
             18.0, 0.0, 36.0,
-            0.0, 54.0, 63.0
+            0.0, 54.0, 63.0,
         ]);
         assert_eq!(target.sub_proj(&attempt), expected_result);
     }
@@ -715,7 +684,7 @@ mod tests {
             DMatrix::from_columns(&[
                 sphere(1.0, 0.0, 0.0, a),
                 sphere(-0.5, a, 0.0, a),
-                sphere(-0.5, -a, 0.0, a)
+                sphere(-0.5, -a, 0.0, a),
             ])
         };
         let state = SearchState::from_config(&gram, config);
@@ -729,7 +698,7 @@ mod tests {
     fn frozen_entry_test() {
         let mut problem = ConstraintProblem::from_guess(&[
             point(0.0, 0.0, 2.0),
-            sphere(0.0, 0.0, 0.0, 0.95)
+            sphere(0.0, 0.0, 0.0, 0.95),
         ]);
         for j in 0..2 {
             for k in j..2 {
@@ -773,7 +742,7 @@ mod tests {
         let mut problem = ConstraintProblem::from_guess(&[
             sphere(0.0, 0.0, 0.0, -2.0),
             sphere(0.0, 0.0, 1.0, 1.0),
-            sphere(0.0, 0.0, -1.0, 1.0)
+            sphere(0.0, 0.0, -1.0, 1.0),
         ]);
         for j in 0..3 {
             for k in j..3 {
@@ -803,8 +772,8 @@ mod tests {
             DMatrix::<f64>::from_column_slice(UNIFORM_DIM, assembly_dim, &[
                 0.0, 0.0,  0.0,  0.0,
                 0.0, 0.0, -0.5, -0.5,
-                0.0, 0.0, -0.5,  0.5
-            ])
+                0.0, 0.0, -0.5,  0.5,
+            ]),
         ];
         let tangent_motions_std = vec![
             basis_matrix((0, 1), element_dim, assembly_dim),
@@ -814,8 +783,8 @@ mod tests {
             DMatrix::<f64>::from_column_slice(element_dim, assembly_dim, &[
                 0.0, 0.0,  0.0,  0.00,  0.0,
                 0.0, 0.0, -1.0, -0.25, -1.0,
-                0.0, 0.0, -1.0,  0.25,  1.0
-            ])
+                0.0, 0.0, -1.0,  0.25,  1.0,
+            ]),
         ];
         
         // confirm that the dimension of the tangent space is no greater than
@@ -891,10 +860,10 @@ mod tests {
                         DVector::from_column_slice(&[0.0, 0.0, 5.0, 0.0]),
                         DVector::from_column_slice(&[0.0, 0.0, 1.0, 0.0]),
                         DVector::from_column_slice(&[-vel_vert_x, -vel_vert_y, -3.0, 0.0]),
-                        DVector::from_column_slice(&[vel_vert_x, vel_vert_y, -3.0, 0.0])
+                        DVector::from_column_slice(&[vel_vert_x, vel_vert_y, -3.0, 0.0]),
                     ]
                 }
-            ).collect::<Vec<_>>()
+            ).collect::<Vec<_>>(),
         ];
         let tangent_motions_std = tangent_motions_unif.iter().map(
             |motion| DMatrix::from_columns(
@@ -927,7 +896,7 @@ mod tests {
                    0.0,        1.0,        0.0, 0.0,             dis[1],
                    0.0,        0.0,        1.0, 0.0,             dis[2],
             2.0*dis[0], 2.0*dis[1], 2.0*dis[2], 1.0, dis.norm_squared(),
-                   0.0,        0.0,        0.0, 0.0,                1.0
+                   0.0,        0.0,        0.0, 0.0,                1.0,
         ])
     }
     
@@ -939,7 +908,7 @@ mod tests {
         const SCALED_TOL: f64 = 1.0e-12;
         let mut problem_orig = ConstraintProblem::from_guess(&[
             sphere(0.0, 0.0, 0.5, 1.0),
-            sphere(0.0, 0.0, -0.5, 1.0)
+            sphere(0.0, 0.0, -0.5, 1.0),
         ]);
         problem_orig.gram.push_sym(0, 0, 1.0);
         problem_orig.gram.push_sym(1, 1, 1.0);
@@ -957,13 +926,13 @@ mod tests {
             let a = 0.5 * FRAC_1_SQRT_2;
             DMatrix::from_columns(&[
                 sphere(a, 0.0, 7.0 + a, 1.0),
-                sphere(-a, 0.0, 7.0 - a, 1.0)
+                sphere(-a, 0.0, 7.0 - a, 1.0),
             ])
         };
         let problem_tfm = ConstraintProblem {
             gram: problem_orig.gram,
+            frozen: problem_orig.frozen,
             guess: guess_tfm,
-            frozen: problem_orig.frozen
         };
         let Realization { result: result_tfm, history: history_tfm } = realize_gram(
             &problem_tfm, SCALED_TOL, 0.5, 0.9, 1.1, 200, 110
@@ -991,7 +960,7 @@ mod tests {
                       0.0, 1.0,            0.0, 0.0, 0.0,
             FRAC_1_SQRT_2, 0.0,  FRAC_1_SQRT_2, 0.0, 0.0,
                       0.0, 0.0,            0.0, 1.0, 0.0,
-                      0.0, 0.0,            0.0, 0.0, 1.0
+                      0.0, 0.0,            0.0, 0.0, 1.0,
         ]);
         let transl = translation(Vector3::new(0.0, 0.0, 7.0));
         let motion_proj_tfm = transl * rot * motion_orig_proj;
diff --git a/app-proto/src/main.rs b/app-proto/src/main.rs
index f905c46..a03b026 100644
--- a/app-proto/src/main.rs
+++ b/app-proto/src/main.rs
@@ -1,9 +1,6 @@
-mod add_remove;
 mod assembly;
-mod diagnostics;
-mod display;
+mod components;
 mod engine;
-mod outline;
 mod specified;
 
 #[cfg(test)]
@@ -12,23 +9,25 @@ mod tests;
 use std::{collections::BTreeSet, rc::Rc};
 use sycamore::prelude::*;
 
-use add_remove::AddRemove;
 use assembly::{Assembly, Element};
-use diagnostics::Diagnostics;
-use display::Display;
-use outline::Outline;
+use components::{
+    add_remove::AddRemove,
+    diagnostics::Diagnostics,
+    display::Display,
+    outline::Outline,
+};
 
 #[derive(Clone)]
 struct AppState {
     assembly: Assembly,
-    selection: Signal<BTreeSet<Rc<dyn Element>>>
+    selection: Signal<BTreeSet<Rc<dyn Element>>>,
 }
 
 impl AppState {
-    fn new() -> AppState {
-        AppState {
+    fn new() -> Self {
+        Self {
             assembly: Assembly::new(),
-            selection: create_signal(BTreeSet::default())
+            selection: create_signal(BTreeSet::default()),
         }
     }
     
@@ -59,7 +58,7 @@ fn main() {
         provide_context(AppState::new());
         
         view! {
-            div(id="sidebar") {
+            div(id = "sidebar") {
                 AddRemove {}
                 Outline {}
                 Diagnostics {}
diff --git a/app-proto/src/specified.rs b/app-proto/src/specified.rs
index cfe7fc3..788460b 100644
--- a/app-proto/src/specified.rs
+++ b/app-proto/src/specified.rs
@@ -13,12 +13,12 @@ use std::num::ParseFloatError;
 #[readonly::make]
 pub struct SpecifiedValue {
     pub spec: String,
-    pub value: Option<f64>
+    pub value: Option<f64>,
 }
 
 impl SpecifiedValue {
-    pub fn from_empty_spec() -> SpecifiedValue {
-        SpecifiedValue { spec: String::new(), value: None }
+    pub fn from_empty_spec() -> Self {
+        Self { spec: String::new(), value: None }
     }
     
     pub fn is_present(&self) -> bool {
@@ -34,10 +34,10 @@ impl TryFrom<String> for SpecifiedValue {
     
     fn try_from(spec: String) -> Result<Self, Self::Error> {
         if spec.is_empty() {
-            Ok(SpecifiedValue::from_empty_spec())
+            Ok(Self::from_empty_spec())
         } else {
             spec.parse::<f64>().map(
-                |value| SpecifiedValue { spec: spec, value: Some(value) }
+                |value| Self { spec, value: Some(value) }
             )
         }
     }
diff --git a/deploy/.gitignore b/deploy/.gitignore
new file mode 100644
index 0000000..192f529
--- /dev/null
+++ b/deploy/.gitignore
@@ -0,0 +1,5 @@
+/dyna3.zip
+/dyna3/index.html
+/dyna3/dyna3-*.js
+/dyna3/dyna3-*.wasm
+/dyna3/main-*.css
\ No newline at end of file
diff --git a/tools/package-for-deployment.sh b/tools/package-for-deployment.sh
new file mode 100644
index 0000000..fdda434
--- /dev/null
+++ b/tools/package-for-deployment.sh
@@ -0,0 +1,16 @@
+# set paths. this technique for getting the script location comes from
+# `mklement0` on Stack Overflow
+#
+#   https://stackoverflow.com/a/24114056
+#
+TOOLS=$(dirname -- $0)
+SRC="$TOOLS/../app-proto/dist"
+DEST="$TOOLS/../deploy/dyna3"
+
+# remove the old hash-named files
+[ -e "$DEST"/dyna3-*.js ] && rm "$DEST"/dyna3-*.js
+[ -e "$DEST"/dyna3-*.wasm ] && rm "$DEST"/dyna3-*.wasm
+[ -e "$DEST"/main-*.css ] && rm "$DEST"/main-*.css
+
+# copy the distribution
+cp -r "$SRC/." "$DEST"
diff --git a/app-proto/run-examples.sh b/tools/run-examples.sh
similarity index 89%
rename from app-proto/run-examples.sh
rename to tools/run-examples.sh
index 861addf..0946d92 100644
--- a/app-proto/run-examples.sh
+++ b/tools/run-examples.sh
@@ -8,7 +8,7 @@
 # the application prototype
 
 # find the manifest file for the application prototype
-MANIFEST="$(dirname -- $0)/Cargo.toml"
+MANIFEST="$(dirname -- $0)/../app-proto/Cargo.toml"
 
 # set up the command that runs each example
 RUN_EXAMPLE="cargo run --manifest-path $MANIFEST --example"