diff --git a/protocols/schemas/shapes.prs b/protocols/schemas/shapes.prs
index 9295e94..db34423 100644
--- a/protocols/schemas/shapes.prs
+++ b/protocols/schemas/shapes.prs
@@ -5,7 +5,7 @@ Variable = <variable @spriteName string @variable symbol @value any> .
 
 Shape = Mesh / Light / Scale / Move / Rotate / @many [Shape ...] / Texture / Color / Sound / Name / Floor / Nonphysical / Touchable / CSG / Skybox .
 
-Mesh = Sphere / Box / Ground / Plane / External .
+Mesh = Sphere / Box / Ground / Plane / External / @turtle turtle.Shape .
 
 Sphere = <sphere> .
 Box = <box> .
diff --git a/protocols/schemas/turtle.prs b/protocols/schemas/turtle.prs
new file mode 100644
index 0000000..9959ed1
--- /dev/null
+++ b/protocols/schemas/turtle.prs
@@ -0,0 +1,7 @@
+version 1 .
+
+Program = Block .
+Block = [Token ...] .
+Token = @i int / @d double / @b bool / @s string / @v symbol / @block Block .
+
+Shape = <turtle @program Program> .
diff --git a/scene/lobby.pr b/scene/lobby.pr
index e2bace7..5b4b0f1 100644
--- a/scene/lobby.pr
+++ b/scene/lobby.pr
@@ -92,18 +92,58 @@
 ;   <scale <v 0.01 0.01 0.01>
 ;    <external "objects/IKE020001_obj/IKEA-Arild_2_Seat_Sofa-3D.obj">>>>
 
-<sprite "x" []
- <move <v 10.0 1.6 -5.0>
-  <texture ["textures/oak-herringbone-5e80fb40b00c9-1200.jpg"
-            <v 1.0 3.0 1.0>
-            <v 0.0 0.0 0.0>]
-   <sound <stream "https://streams.95bfm.com/stream95">
-    <csg
-     <subtract [
-       <move <v 0.0 0.0 0.5> <scale <v 1.1 3.1 1.1> <mesh <box>>>>
-       <move <v 0.0 0.0 0.5> <scale <v 1.0 3.0 1.0> <mesh <box>>>>
-     ]>
-    >>>>>
+; <sprite "x" []
+;  <move <v 10.0 1.6 -5.0>
+;   <texture ["textures/oak-herringbone-5e80fb40b00c9-1200.jpg"
+;             <v 1.0 3.0 1.0>
+;             <v 0.0 0.0 0.0>]
+;    <sound <stream "https://streams.95bfm.com/stream95">
+;     <csg
+;      <subtract [
+;        <move <v 0.0 0.0 0.5> <scale <v 1.1 3.1 1.1> <mesh <box>>>>
+;        <move <v 0.0 0.0 0.5> <scale <v 1.0 3.0 1.0> <mesh <box>>>>
+;      ]>
+;     >>>>>
+
+; <sprite "tt" []
+;  <move <v 0.0 1.6 0.0>
+;   <turtle [
+;     1 to slen
+;     0.025 to dlen
+;     90 U
+;     dlen 10 * F
+;     PenDown
+;     90 L
+;     [12 L dlen 2 * F] 30 times
+;     90 R
+;     slen F
+;     SetPen
+;     Home
+;     PenDown
+;     [6 CW dlen F] 240 times
+;     PenUp
+;   ]>>>
+
+<sprite "tt" []
+ <move <v 0.0 0.01 0.75>
+  <turtle [
+    1.0 to wallHeight
+    0.1 to wallDepth
+
+    90 U
+    PenDown
+    [wallHeight F 90 L wallDepth F 90 L] 2 times
+    SetPen
+    Home
+
+    [ 10 to k k / [dup F] k times drop ] to ff
+
+    1 CornerDivisions
+    1 1 1 PenScale
+    PenDown
+    1 ff 90 R 1 ff 90 R 1 ff 90 R 1 ff 90 R
+    PenUp
+  ]>>>
 
 ; <Exit "y" "lobby">
 ; <sprite "y" []
diff --git a/src/shapes.ts b/src/shapes.ts
index cde6e6a..6a9cc16 100644
--- a/src/shapes.ts
+++ b/src/shapes.ts
@@ -20,9 +20,10 @@ import {
     Vector2,
     Vector3,
 } from '@babylonjs/core/Legacy/legacy';
-import { Dataflow, IdentityMap, KeyedDictionary, Ref, Value, is } from "@syndicate-lang/core";
+import { Dataflow, IdentityMap, KeyedDictionary, Ref, Value, is, fromJS } from "@syndicate-lang/core";
 
 import * as Shapes from './gen/shapes.js';
+import { TurtleVM } from './turtle.js';
 
 export class Environment {
     fields = new IdentityMap<symbol, Dataflow.Field<Value<Ref>>>();
@@ -260,6 +261,12 @@ export function buildMesh(
                 }),
             };
         }
+        case "turtle": {
+            const t = new TurtleVM(name, scene, meshSpec.value.program.map(fromJS));
+            t.debug = true;
+            t.exec();
+            return { rootnode: t.container };
+        }
     }
 }