diff --git a/app-proto/inversive-display/src/main.rs b/app-proto/inversive-display/src/main.rs
index 350c81c..d351149 100644
--- a/app-proto/inversive-display/src/main.rs
+++ b/app-proto/inversive-display/src/main.rs
@@ -172,6 +172,8 @@ fn main() {
         let yaw_left = create_signal(0.0);
         let roll_ccw = create_signal(0.0);
         let roll_cw = create_signal(0.0);
+        let zoom_in = create_signal(0.0);
+        let zoom_out = create_signal(0.0);
         
         // controls for general example
         let gen_controls = create_node_ref();
@@ -262,21 +264,12 @@ fn main() {
             let mut last_time = 0.0;
             
             // scene parameters
-            const NAV_SPEED: f64 = 0.4; // in radians per second
+            const ROT_SPEED: f64 = 0.4; // in radians per second
             const TURNTABLE_SPEED: f64 = 0.1; // in radians per second
+            const ZOOM_SPEED: f64 = 0.15;
             let mut orientation = DMatrix::<f64>::identity(5, 5);
             let mut rotation = DMatrix::<f64>::identity(5, 5);
-            let location = {
-                const LEN: f64 = -5.0;
-                const LEN_SQ: f64 = LEN*LEN;
-                DMatrix::from_column_slice(5, 5, &[
-                    1.0, 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,    LEN,
-                    0.0, 0.0, 2.0*LEN, 1.0, LEN_SQ,
-                    0.0, 0.0,     0.0, 0.0,    1.0
-                ])
-            };
+            let mut location_z: f64 = 5.0;
             
             /* INSTRUMENTS */
             let performance = window().unwrap().performance().unwrap();
@@ -389,6 +382,8 @@ fn main() {
                 let yaw_left_val = yaw_left.get();
                 let roll_ccw_val = roll_ccw.get();
                 let roll_cw_val = roll_cw.get();
+                let zoom_in_val = zoom_in.get();
+                let zoom_out_val = zoom_out.get();
                 let turntable_val = turntable.get();
                 
                 // update the construction's orientation
@@ -398,7 +393,7 @@ fn main() {
                     let roll = roll_ccw_val - roll_cw_val;
                     let ang_vel_from_keyboard =
                         if pitch != 0.0 || yaw != 0.0 || roll != 0.0 {
-                            NAV_SPEED * Vector3::new(-pitch, yaw, roll).normalize()
+                            ROT_SPEED * Vector3::new(-pitch, yaw, roll).normalize()
                         } else {
                             Vector3::zeros()
                         };
@@ -416,6 +411,10 @@ fn main() {
                 );
                 orientation = &rotation * &orientation;
                 
+                // update the construction's location
+                let zoom = zoom_out_val - zoom_in_val;
+                location_z *= (time_step * ZOOM_SPEED * zoom).exp();
+                
                 if scene_changed.get() {
                     /* INSTRUMENTS */
                     // measure mean frame interval
@@ -427,6 +426,16 @@ fn main() {
                     }
                     
                     // find the map from construction space to world space
+                    let location = {
+                        let u = -location_z;
+                        DMatrix::from_column_slice(5, 5, &[
+                            1.0, 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,   u,
+                            0.0, 0.0, 2.0*u, 1.0, u*u,
+                            0.0, 0.0,   0.0, 0.0, 1.0
+                        ])
+                    };
                     let construction_to_world = &location * &orientation;
                     
                     // update the construction
@@ -492,6 +501,8 @@ fn main() {
                         || yaw_right_val != 0.0
                         || roll_cw_val != 0.0
                         || roll_ccw_val != 0.0
+                        || zoom_in_val != 0.0
+                        || zoom_out_val != 0.0
                         || turntable_val
                     );
                 } else {
@@ -504,11 +515,14 @@ fn main() {
         
         let set_nav_signal = move |event: KeyboardEvent, value: f64| {
             let mut navigating = true;
+            let shift = event.shift_key();
             match event.key().as_str() {
+                "ArrowUp" if shift => zoom_in.set(value),
+                "ArrowDown" if shift => zoom_out.set(value),
                 "ArrowUp" => pitch_up.set(value),
                 "ArrowDown" => pitch_down.set(value),
-                "ArrowRight" if event.shift_key() => roll_cw.set(value),
-                "ArrowLeft" if event.shift_key() => roll_ccw.set(value),
+                "ArrowRight" if shift => roll_cw.set(value),
+                "ArrowLeft" if shift => roll_ccw.set(value),
                 "ArrowRight" => yaw_right.set(value),
                 "ArrowLeft" => yaw_left.set(value),
                 _ => navigating = false
@@ -551,8 +565,12 @@ fn main() {
                         if event.key() == "Shift" {
                             roll_cw.set(yaw_right.get());
                             roll_ccw.set(yaw_left.get());
+                            zoom_in.set(pitch_up.get());
+                            zoom_out.set(pitch_down.get());
                             yaw_right.set(0.0);
                             yaw_left.set(0.0);
+                            pitch_up.set(0.0);
+                            pitch_down.set(0.0);
                         } else {
                             set_nav_signal(event, 1.0);
                         }
@@ -561,8 +579,12 @@ fn main() {
                         if event.key() == "Shift" {
                             yaw_right.set(roll_cw.get());
                             yaw_left.set(roll_ccw.get());
+                            pitch_up.set(zoom_in.get());
+                            pitch_down.set(zoom_out.get());
                             roll_cw.set(0.0);
                             roll_ccw.set(0.0);
+                            zoom_in.set(0.0);
+                            zoom_out.set(0.0);
                         } else {
                             set_nav_signal(event, 0.0);
                         }