diff --git a/etc/options.html b/etc/options.html
index e618cf5..b512c0e 100644
--- a/etc/options.html
+++ b/etc/options.html
@@ -18,8 +18,12 @@
   Alter execution of the translated applet: <br/>
   <label for="showall">Show all applet entities, even hidden ones</label>
   <input type="checkbox" id="showall"><br/>
-  <label for="showaux">Show geogebra auxiliaries (not in applet)</label>
+  <label for="showaux">Show GeoGebra auxiliaries (not in applet)</label>
   <input type="checkbox" id="showaux">
+  <br/>
+  <br/>
+  <label for="algebra">Show the GeoGebra algebra pane</label>
+  <input type="checkbox" id="algebra">
   <script src="options.js" type="module"></script>
 </body>
 
diff --git a/src/adapptext.civet b/src/adapptext.civet
index 8b0be59..5138235 100644
--- a/src/adapptext.civet
+++ b/src/adapptext.civet
@@ -64,7 +64,7 @@ document.addEventListener "DOMContentLoaded", async =>
             use3d = true
             break
       codebase .= browser.runtime.getURL 'deps/GeoGebra/HTML5/5.0/'
-      codebase += use3d ? 'web3d' : 'webSimple'
+      codebase += (use3d or config.algebra) ? 'web3d' : 'webSimple'
       adapParams: AdapParams := {codebase, config, joyceApplets }
       apars := JSON.stringify(adapParams)
       addScriptTag(browser.runtime.getURL 'deps/GeoGebra/deployggb.js').then =>
diff --git a/src/adapptlet.civet b/src/adapptlet.civet
index e049d75..a08a6a2 100644
--- a/src/adapptlet.civet
+++ b/src/adapptlet.civet
@@ -35,6 +35,20 @@ type Description
 // with the otherName property:
 type JoyceElements = Record<AnyName, Description>
 
+adapptScript := findAdappt() as HTMLScriptElement
+
+function findAdappt()
+  scripts := document.querySelectorAll 'script'
+  for scrip of scripts
+     src := scrip.getAttribute 'src'
+     if src and src.includes 'adapptlet'
+        return scrip
+
+adapParams: AdapParams :=
+   typeof GGBApplet is 'undefined'
+      ? {loader: 'https://www.geogebra.org/apps/deployggb.js', joyceApplets: []}
+      : JSON.parse(adapptScript.dataset.params ?? '') as AdapParams
+
 function postApplets(jApplets: AppletDescription[], codebase = '')
    for each jApp of jApplets
       params := {
@@ -48,7 +62,7 @@ function postApplets(jApplets: AppletDescription[], codebase = '')
             backgroundRGB := [255, 255, 255] as RGB
             config3d := contains3d jApp.params
             if config3d
-               worked := api.enable3D true
+               api.enable3D true
                api.setPerspective 'T'
                // Get rid of the xy-plane indicator
                xml .= api.getXML()
@@ -56,6 +70,8 @@ function postApplets(jApplets: AppletDescription[], codebase = '')
                api.setXML xml
             else if codebase.includes 'web3d'
                api.setPerspective 'G'
+            if adapParams.config?.algebra
+               api.setPerspective '+A'
             for name, value in jApp.params
                dispatchJcommand
                   api, name, value, elements, backgroundRGB, config3d
@@ -78,22 +94,6 @@ function postApplets(jApplets: AppletDescription[], codebase = '')
       if codebase then geoApp.setHTML5Codebase codebase
       geoApp.inject jApp.id
 
-adapptScript := findAdappt() as HTMLScriptElement
-
-function findAdappt()
-  scripts := document.querySelectorAll 'script'
-  for scrip of scripts
-     src := scrip.getAttribute 'src'
-     if src and src.includes 'adapptlet'
-        return scrip
-
-console.log 'In script', document.currentScript, adapptScript
-
-adapParams: AdapParams :=
-   typeof GGBApplet is 'undefined'
-      ? {loader: 'https://www.geogebra.org/apps/deployggb.js', joyceApplets: []}
-      : JSON.parse(adapptScript.dataset.params ?? '') as AdapParams
-
 // Always use the final joyceApplets if there are any:
 if joyceApplets.length
    adapParams.joyceApplets = joyceApplets
@@ -412,12 +412,24 @@ function geoname(jname: JoyceName, elements: JoyceElements): GeoName
    return .= 'Geo' + numCode.toString(36);
    return += '1' while return.value in elements
 
+// Helper for similar point/line functions:
+function cutoffExtend(
+      method: string, pt: string[], point?: string[], line?: string[]
+      ): [string, string]
+   direction .= `UnitVector(Vector(${pt[0]},${pt[1]}))`
+   if line and (not point or point[0] !== pt[0])
+      direction = `UnitVector(${line[0]})`
+   displacement := `Distance(${pt[2]}, ${pt[3]})*${direction}`
+   source := method is 'cutoff' ? pt[0] : pt[1]
+   [source, displacement]
+
 // All of the detailed semantics of each available command lies in this
 // function.
 classHandler: Record<JoyceClass, ClassHandler> :=
    point: (name, method, args, index, is3d): Commander =>
       return := freshCommander()
       {commands, callbacks, parts, auxiliaries} := return.value
+      zeroVector := is3d ? 'Vector((0,0,0))' : 'Vector((0,0))'
       aux := name + 'aUx'
       parts[0].push name
       switch method
@@ -440,22 +452,25 @@ classHandler: Record<JoyceClass, ClassHandler> :=
                `${aux}4 = Rotate(${start}, ${aux}3/${n}, ${center}${inPlane})`
                `${name} = Intersect(${destination}, Ray(${center}, ${aux}4))`
             auxiliaries.push ...[2..4].map (i) => `${aux}${i}`
-         'extend'
-            sp := args.subpoints
-            unless sp then return
-            direction .= `UnitVector(Vector(${sp[0]},${sp[1]}))`
-            if args.line and (
-                  not args.point or args.point[0] !== sp[0])
-               direction = `UnitVector(${args.line[0]})`
-            displacement := `Distance(${sp[2]}, ${sp[3]})*${direction}`
-            commands.push `${name} = Translate(${sp[1]}, ${displacement})`
+         'circleSlider'
+            unless args.circle then return
+            commands.push `${name} = Point(${args.circle[0]})`
+            if args.scalar and args.scalar.length
+               callbacks.push (api: AppletObject) =>
+                  api.setCoords name, ...args.scalar as XYZ
+         /cutoff|extend/
+            pt := args.subpoints
+            unless pt and pt.length is 4 then return
+            [source, displacement] :=
+               cutoffExtend method, pt, args.point, args.line
+            commands.push `${name} = Translate(${source}, ${displacement})`
          'first'
             unless args.subpoints then return
-            commands.push `${name} = ${args.subpoints[0]}`
+            commands.push `${name} = Point(${args.subpoints[0]},${zeroVector})`
          /fixed|free/
             coords := args.scalar
             unless coords then return
-            commands.push `${name} = (${coords.join ','})`
+            commands.push `${name} = Point({${coords.join ','}})`
             if method is 'fixed'
                callbacks.push (api: AppletObject) => api.setFixed name, true
          'foot'
@@ -476,7 +491,8 @@ classHandler: Record<JoyceClass, ClassHandler> :=
             commands.push `${name} = Intersect(${l1},${e2})`
          'last'
             unless args.subpoints then return
-            commands.push `${name} = ${args.subpoints.at(-1)}`
+            commands.push
+               `${name} = Point(${args.subpoints.at(-1)}, ${zeroVector})`
          'lineSegmentSlider'
             segment .= args.line?[0]
             unless segment
@@ -528,7 +544,7 @@ classHandler: Record<JoyceClass, ClassHandler> :=
             commands.push
                `${name} = Vertex(${args.polygon?[0]},${args.scalar?[0]})`
 
-   line: (name, method, args) =>
+   line: (name, method, args, index, is3d) =>
       return := freshCommander()
       return.value.ends = ['', '']
       {commands, callbacks, parts, auxiliaries, ends} := return.value
@@ -536,10 +552,62 @@ classHandler: Record<JoyceClass, ClassHandler> :=
       parts[1].push name
       madeSegment .= false
       switch method
+         'bichord'
+            // To match Joyce, we need to get the ordering here correct.
+            // we want the order so that start -> end sweeping past the
+            // center of the other circle is counterclockwise in the first
+            // circle
+            cr := args.circle
+            unless cr return
+            commands.push ...[1..2].map (n) =>
+              `${aux}${n} = Intersect(${cr[0]}, ${cr[1]}, ${n})`
+            inPlane := is3d ? `Plane(${cr[0]})` : ''
+            ctr := cr.map (c) => `Center(${c})`
+            condition := (`Angle(${aux}1,${ctr[0]},${ctr[1]}${inPlane})`
+               + `< Angle(${aux}2,${ctr[0]},${ctr[1]}${inPlane})`)
+            commands.push
+              `${aux}3 = If(${condition}, ${aux}2, ${aux}1)`
+              `${aux}4 = If(${condition}, ${aux}1, ${aux}2)`
+            ends[0] = aux + 3
+            ends[1] = aux + 4
+            auxiliaries.push ...[1..4].map (n) => aux + n
+         'chord'
+            // To match Joyce, we need to get the ordering here correct.
+            // The complicated condition about distances is modeled after
+            // Joyce's code, but it boils down to: take the endpoint of the
+            // chord closest to the first subpoint, unless that first
+            // subpoint is essentially at the midpoint of the chord, in
+            // which case start with the endpoint nearest the second subpoint.
+            unless args.subpoints and args.circle then return
+            // We intersect with the whole line, not just the segment:
+            line := `Line(${args.subpoints.join ','})`
+            pA := args.subpoints[0]
+            pB := args.subpoints[1]
+            commands.push ...[1..2].map (n) =>
+              `${aux}${n} = Intersect(${args.circle}, ${line}, ${n})`
+            s := `Distance(${aux}1,${aux}2)`
+            d := `Distance(${aux}1,${pA}) - Distance(${aux}2,${pA})`
+            condition := (`If(${s}/10^9 < abs(${d}), ${d} > 0,`
+               + `Distance(${aux}2,${pB}) < Distance(${aux}1,${pB}))`)
+            commands.push
+              `${aux}3 = If(${condition}, ${aux}2, ${aux}1)`
+              `${aux}4 = If(${condition}, ${aux}1, ${aux}2)`
+            ends[0] = aux + 3
+            ends[1] = aux + 4
+            auxiliaries.push ...[1..4].map (n) => aux + n
          'connect'
             unless args.subpoints and args.subpoints.length is 2 then return
             ends[0] = args.subpoints[0]
             ends[1] = args.subpoints[1]
+         /cutoff|extend/
+            pt := args.subpoints
+            unless pt and pt.length is 4 then return
+            [source, displacement] :=
+               cutoffExtend method, pt, args.point, args.line
+            ends[0] = source
+            commands.push `${aux} = Translate(${source}, ${displacement})`
+            auxiliaries.push aux
+            ends[1] = aux
          'parallel'
             unless args.subpoints then return
             [newStart, oldStart, oldEnd] := args.subpoints
@@ -555,24 +623,6 @@ classHandler: Record<JoyceClass, ClassHandler> :=
                madeSegment = true
             else
                commands.push `${aux}2 = Translate(${oldEnd}, ${aux}1)`
-         'chord'
-            // To match Joyce, we need to get the ordering here correct.
-            // ends[0] should be the one closer to args.subpoints[0]
-            unless args.subpoints and args.circle then return
-            line := `Line(${args.subpoints.join ','})`
-            pt := args.subpoints[0]
-            commands.push ...[1..2].map (n) =>
-              `${aux}${n} = Intersect(${args.circle}, ${line}, ${n})`
-            condition := `Distance(${aux}2,${pt}) < Distance(${aux}1,${pt})`
-            // NOTE: Joyce's code has special case for when pt is almost
-            // at midpoint of chord; in that case, it starts at endpoint
-            // closer to the second subpoint... postponing that nicety
-            commands.push
-              `${aux}3 = If(${condition}, ${aux}2, ${aux}1)`
-              `${aux}4 = If(${condition}, ${aux}1, ${aux}2)`
-            ends[0] = aux + 3
-            ends[1] = aux + 4
-            auxiliaries.push ...[1..4].map (n) => aux + n
       unless madeSegment
          commands.push `${name} = Segment(${ends[0]},${ends[1]})`
       callbacks.push (api: AppletObject) => api.setLabelVisible name, true
@@ -585,9 +635,19 @@ classHandler: Record<JoyceClass, ClassHandler> :=
       parts[1].push name
       switch method
          'radius'
-            unless args.subpoints then return
-            [center, point] := args.subpoints
-            commands.push `${name} = Circle(${center}, ${point})`
+            pt := args.subpoints
+            unless pt then return
+            inPlane := args.plane ? `, ${args.plane[0]}` : ''
+            switch pt.length
+               when 2
+                  [center, point] := pt
+                  commands.push
+                     `${name} = Circle(${center}, ${point}${inPlane})`
+               when 3
+                  center := pt[0]
+                  radius := `Distance(${pt[1]}, ${pt[2]})`
+                  commands.push
+                     `${name} = Circle(${center}, ${radius}${inPlane})`
       callbacks.push (api: AppletObject) => api.setLabelVisible name, true
 
    polygon: (name, method, args, index) =>
diff --git a/src/adapptypes.civet b/src/adapptypes.civet
index 5abf456..72d28ea 100644
--- a/src/adapptypes.civet
+++ b/src/adapptypes.civet
@@ -1,4 +1,5 @@
-export const flags = ['color', 'commands', 'showall', 'showaux'] as const
+export const flags = [
+   'color', 'commands', 'showall', 'showaux', 'algebra'] as const
 export type FlagType = (typeof flags)[number]
 export type ConfigType = Partial<Record<FlagType, boolean>>