diff --git a/assets/prelude.ld b/assets/prelude.ld
index 03ce4ae..8907b62 100644
--- a/assets/prelude.ld
+++ b/assets/prelude.ld
@@ -1434,9 +1434,7 @@ fn apply_command {
 			(:home) -> do state > 
 				assoc (_, :position, (0, 0)) >
 				assoc (_, :heading, 0)
-			& (:clear) -> do state >
-			& 	assoc (state, :position, (0, 0)) >
-			& 	assoc (_, :heading, 0)
+			(:clear) -> state
 			(:right, turns) -> update (state, :heading, add (_, turns))
 			(:left, turns) -> update (state, :heading, sub (_, turns))
 			(:forward, steps) -> {
diff --git a/pkg/p5.js b/pkg/p5.js
index a8e36cd..e5eb4dd 100644
--- a/pkg/p5.js
+++ b/pkg/p5.js
@@ -1,13 +1,9 @@
 import {eq_vect, eq_color, resolve_color, get_turtle_color, set_turtle_color, turtle_radius, turtle_angle, turn_to_rad, turtle_init, command_to_state, background_color, rotate, last} from "./turtle_geometry.js"
 
 function states_to_call (prev, curr) {
-  console.log(prev)
-  console.log(curr)
-  const calls = []
-  // whose state should we use?
-  // pen states will only differ on more than one property
-  // if we use `loadstate`
-  // my sense is `prev`, but that may change
+  // console.log(prev)
+  // console.log(curr)
+  let calls = []
   if (prev.pendown && !eq_vect(prev.position, curr.position)) {
     calls.push(["line", prev.position[0], prev.position[1], curr.position[0], curr.position[1]])
   }
@@ -17,6 +13,9 @@ function states_to_call (prev, curr) {
   if (curr.penwidth !== prev.penwidth) {
     calls.push(["strokeWeight", curr.penwidth])
   }
+  if (curr.clear) {
+    calls.push("clear")
+  }
   return calls
 }
 
@@ -69,25 +68,36 @@ export function p5 (commands) {
     let prev_state = last(all_states[turtle_id])
     const new_state = command_to_state(prev_state, this_command)
     all_states[turtle_id].push(new_state)
+
   }
   // console.log(all_states)
   const [r, g, b, _] = resolve_color(background_color)  
   if ((r + g + b)/3 > 128) set_turtle_color([0, 0, 0, 150])
   const p5_calls = [...p5_call_root()]
   for (const states of Object.values(all_states)) {
-    p5_calls.push(["strokeWeight", 1])
-    p5_calls.push(["stroke", 255])
+    // console.log(states)
+    let my_calls = []
     for (let i = 1; i < states.length; ++i) {
       const prev = states[i - 1]
       const curr = states[i]
       const calls = states_to_call(prev, curr)
       for (const call of calls) {
-        p5_calls.push(call)
+        // console.log(call)
+        if (call === "clear") {
+          my_calls = []
+        } else {
+          my_calls.push(call)
+        }
       }
     }
-    p5_calls[0] = ["background", ...resolve_color(background_color)]
-    p5_render_turtle(states[states.length - 1], p5_calls)
+    p5_calls.push(["strokeWeight", 1])
+    p5_calls.push(["stroke", 255])
+    for (const call of my_calls) {
+      p5_calls.push(call)
+    }
+    p5_render_turtle(last(states), p5_calls)
   }
+  p5_calls[0] = ["background", ...resolve_color(background_color)]
   p5_calls.push(["pop"])
   return p5_calls
 }
diff --git a/pkg/rudus.d.ts b/pkg/rudus.d.ts
index b5e984a..86c1521 100644
--- a/pkg/rudus.d.ts
+++ b/pkg/rudus.d.ts
@@ -11,11 +11,11 @@ export interface InitOutput {
   readonly __externref_table_alloc: () => number;
   readonly __wbindgen_export_2: WebAssembly.Table;
   readonly __wbindgen_free: (a: number, b: number, c: number) => void;
-  readonly __wbindgen_export_4: WebAssembly.Table;
   readonly __wbindgen_malloc: (a: number, b: number) => number;
   readonly __wbindgen_realloc: (a: number, b: number, c: number, d: number) => number;
-  readonly closure354_externref_shim: (a: number, b: number, c: any) => void;
-  readonly closure377_externref_shim: (a: number, b: number, c: any, d: any) => void;
+  readonly __wbindgen_export_6: WebAssembly.Table;
+  readonly closure361_externref_shim: (a: number, b: number, c: any) => void;
+  readonly closure384_externref_shim: (a: number, b: number, c: any, d: any) => void;
   readonly __wbindgen_start: () => void;
 }
 
diff --git a/pkg/rudus.js b/pkg/rudus.js
index 1b02a9a..5e830e1 100644
--- a/pkg/rudus.js
+++ b/pkg/rudus.js
@@ -51,6 +51,73 @@ function getStringFromWasm0(ptr, len) {
     return cachedTextDecoder.decode(getUint8ArrayMemory0().subarray(ptr, ptr + len));
 }
 
+let WASM_VECTOR_LEN = 0;
+
+const cachedTextEncoder = (typeof TextEncoder !== 'undefined' ? new TextEncoder('utf-8') : { encode: () => { throw Error('TextEncoder not available') } } );
+
+const encodeString = (typeof cachedTextEncoder.encodeInto === 'function'
+    ? function (arg, view) {
+    return cachedTextEncoder.encodeInto(arg, view);
+}
+    : function (arg, view) {
+    const buf = cachedTextEncoder.encode(arg);
+    view.set(buf);
+    return {
+        read: arg.length,
+        written: buf.length
+    };
+});
+
+function passStringToWasm0(arg, malloc, realloc) {
+
+    if (typeof(arg) !== 'string') throw new Error(`expected a string argument, found ${typeof(arg)}`);
+
+    if (realloc === undefined) {
+        const buf = cachedTextEncoder.encode(arg);
+        const ptr = malloc(buf.length, 1) >>> 0;
+        getUint8ArrayMemory0().subarray(ptr, ptr + buf.length).set(buf);
+        WASM_VECTOR_LEN = buf.length;
+        return ptr;
+    }
+
+    let len = arg.length;
+    let ptr = malloc(len, 1) >>> 0;
+
+    const mem = getUint8ArrayMemory0();
+
+    let offset = 0;
+
+    for (; offset < len; offset++) {
+        const code = arg.charCodeAt(offset);
+        if (code > 0x7F) break;
+        mem[ptr + offset] = code;
+    }
+
+    if (offset !== len) {
+        if (offset !== 0) {
+            arg = arg.slice(offset);
+        }
+        ptr = realloc(ptr, len, len = offset + arg.length * 3, 1) >>> 0;
+        const view = getUint8ArrayMemory0().subarray(ptr + offset, ptr + len);
+        const ret = encodeString(arg, view);
+        if (ret.read !== arg.length) throw new Error('failed to pass whole string');
+        offset += ret.written;
+        ptr = realloc(ptr, len, offset, 1) >>> 0;
+    }
+
+    WASM_VECTOR_LEN = offset;
+    return ptr;
+}
+
+let cachedDataViewMemory0 = null;
+
+function getDataViewMemory0() {
+    if (cachedDataViewMemory0 === null || cachedDataViewMemory0.buffer.detached === true || (cachedDataViewMemory0.buffer.detached === undefined && cachedDataViewMemory0.buffer !== wasm.memory.buffer)) {
+        cachedDataViewMemory0 = new DataView(wasm.memory.buffer);
+    }
+    return cachedDataViewMemory0;
+}
+
 function isLikeNone(x) {
     return x === undefined || x === null;
 }
@@ -64,7 +131,7 @@ function _assertBoolean(n) {
 const CLOSURE_DTORS = (typeof FinalizationRegistry === 'undefined')
     ? { register: () => {}, unregister: () => {} }
     : new FinalizationRegistry(state => {
-    wasm.__wbindgen_export_4.get(state.dtor)(state.a, state.b)
+    wasm.__wbindgen_export_6.get(state.dtor)(state.a, state.b)
 });
 
 function makeMutClosure(arg0, arg1, dtor, f) {
@@ -80,7 +147,7 @@ function makeMutClosure(arg0, arg1, dtor, f) {
             return f(a, state.b, ...args);
         } finally {
             if (--state.cnt === 0) {
-                wasm.__wbindgen_export_4.get(state.dtor)(a, state.b);
+                wasm.__wbindgen_export_6.get(state.dtor)(a, state.b);
                 CLOSURE_DTORS.unregister(state);
             } else {
                 state.a = a;
@@ -156,73 +223,6 @@ function debugString(val) {
     // TODO we could test for more things here, like `Set`s and `Map`s.
     return className;
 }
-
-let WASM_VECTOR_LEN = 0;
-
-const cachedTextEncoder = (typeof TextEncoder !== 'undefined' ? new TextEncoder('utf-8') : { encode: () => { throw Error('TextEncoder not available') } } );
-
-const encodeString = (typeof cachedTextEncoder.encodeInto === 'function'
-    ? function (arg, view) {
-    return cachedTextEncoder.encodeInto(arg, view);
-}
-    : function (arg, view) {
-    const buf = cachedTextEncoder.encode(arg);
-    view.set(buf);
-    return {
-        read: arg.length,
-        written: buf.length
-    };
-});
-
-function passStringToWasm0(arg, malloc, realloc) {
-
-    if (typeof(arg) !== 'string') throw new Error(`expected a string argument, found ${typeof(arg)}`);
-
-    if (realloc === undefined) {
-        const buf = cachedTextEncoder.encode(arg);
-        const ptr = malloc(buf.length, 1) >>> 0;
-        getUint8ArrayMemory0().subarray(ptr, ptr + buf.length).set(buf);
-        WASM_VECTOR_LEN = buf.length;
-        return ptr;
-    }
-
-    let len = arg.length;
-    let ptr = malloc(len, 1) >>> 0;
-
-    const mem = getUint8ArrayMemory0();
-
-    let offset = 0;
-
-    for (; offset < len; offset++) {
-        const code = arg.charCodeAt(offset);
-        if (code > 0x7F) break;
-        mem[ptr + offset] = code;
-    }
-
-    if (offset !== len) {
-        if (offset !== 0) {
-            arg = arg.slice(offset);
-        }
-        ptr = realloc(ptr, len, len = offset + arg.length * 3, 1) >>> 0;
-        const view = getUint8ArrayMemory0().subarray(ptr + offset, ptr + len);
-        const ret = encodeString(arg, view);
-        if (ret.read !== arg.length) throw new Error('failed to pass whole string');
-        offset += ret.written;
-        ptr = realloc(ptr, len, offset, 1) >>> 0;
-    }
-
-    WASM_VECTOR_LEN = offset;
-    return ptr;
-}
-
-let cachedDataViewMemory0 = null;
-
-function getDataViewMemory0() {
-    if (cachedDataViewMemory0 === null || cachedDataViewMemory0.buffer.detached === true || (cachedDataViewMemory0.buffer.detached === undefined && cachedDataViewMemory0.buffer !== wasm.memory.buffer)) {
-        cachedDataViewMemory0 = new DataView(wasm.memory.buffer);
-    }
-    return cachedDataViewMemory0;
-}
 /**
  * @param {string} src
  * @returns {Promise<void>}
@@ -240,13 +240,13 @@ function _assertNum(n) {
 function __wbg_adapter_20(arg0, arg1, arg2) {
     _assertNum(arg0);
     _assertNum(arg1);
-    wasm.closure354_externref_shim(arg0, arg1, arg2);
+    wasm.closure361_externref_shim(arg0, arg1, arg2);
 }
 
-function __wbg_adapter_40(arg0, arg1, arg2, arg3) {
+function __wbg_adapter_46(arg0, arg1, arg2, arg3) {
     _assertNum(arg0);
     _assertNum(arg1);
-    wasm.closure377_externref_shim(arg0, arg1, arg2, arg3);
+    wasm.closure384_externref_shim(arg0, arg1, arg2, arg3);
 }
 
 async function __wbg_load(module, imports) {
@@ -291,6 +291,17 @@ function __wbg_get_imports() {
         const ret = arg0.call(arg1, arg2);
         return ret;
     }, arguments) };
+    imports.wbg.__wbg_error_7534b8e9a36f1ab4 = function() { return logError(function (arg0, arg1) {
+        let deferred0_0;
+        let deferred0_1;
+        try {
+            deferred0_0 = arg0;
+            deferred0_1 = arg1;
+            console.error(getStringFromWasm0(arg0, arg1));
+        } finally {
+            wasm.__wbindgen_free(deferred0_0, deferred0_1, 1);
+        }
+    }, arguments) };
     imports.wbg.__wbg_io_5a3c8ea72d8c6ea3 = function() { return handleError(function (arg0, arg1) {
         let deferred0_0;
         let deferred0_1;
@@ -313,7 +324,7 @@ function __wbg_get_imports() {
                 const a = state0.a;
                 state0.a = 0;
                 try {
-                    return __wbg_adapter_40(a, state0.b, arg0, arg1);
+                    return __wbg_adapter_46(a, state0.b, arg0, arg1);
                 } finally {
                     state0.a = a;
                 }
@@ -324,6 +335,10 @@ function __wbg_get_imports() {
             state0.a = state0.b = 0;
         }
     }, arguments) };
+    imports.wbg.__wbg_new_8a6f238a6ece86ea = function() { return logError(function () {
+        const ret = new Error();
+        return ret;
+    }, arguments) };
     imports.wbg.__wbg_newnoargs_105ed471475aaf50 = function() { return logError(function (arg0, arg1) {
         const ret = new Function(getStringFromWasm0(arg0, arg1));
         return ret;
@@ -347,6 +362,13 @@ function __wbg_get_imports() {
         const ret = Promise.resolve(arg0);
         return ret;
     }, arguments) };
+    imports.wbg.__wbg_stack_0ed75d68575b0f3c = function() { return logError(function (arg0, arg1) {
+        const ret = arg1.stack;
+        const ptr1 = passStringToWasm0(ret, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+        const len1 = WASM_VECTOR_LEN;
+        getDataViewMemory0().setInt32(arg0 + 4 * 1, len1, true);
+        getDataViewMemory0().setInt32(arg0 + 4 * 0, ptr1, true);
+    }, arguments) };
     imports.wbg.__wbg_static_accessor_GLOBAL_88a902d13a557d07 = function() { return logError(function () {
         const ret = typeof global === 'undefined' ? null : global;
         return isLikeNone(ret) ? 0 : addToExternrefTable0(ret);
@@ -381,8 +403,8 @@ function __wbg_get_imports() {
         _assertBoolean(ret);
         return ret;
     };
-    imports.wbg.__wbindgen_closure_wrapper8119 = function() { return logError(function (arg0, arg1, arg2) {
-        const ret = makeMutClosure(arg0, arg1, 355, __wbg_adapter_20);
+    imports.wbg.__wbindgen_closure_wrapper8180 = function() { return logError(function (arg0, arg1, arg2) {
+        const ret = makeMutClosure(arg0, arg1, 362, __wbg_adapter_20);
         return ret;
     }, arguments) };
     imports.wbg.__wbindgen_debug_string = function(arg0, arg1) {
diff --git a/pkg/rudus_bg.wasm b/pkg/rudus_bg.wasm
index 9b9a598..d38209f 100644
--- a/pkg/rudus_bg.wasm
+++ b/pkg/rudus_bg.wasm
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:e8e8b8752e877bfcad162074189d7d38423e458f5204400c409796841f8884e9
-size 16769183
+oid sha256:683a7e967425d20a25b784a452f64aa86bdc81adc80f90be34567c74ab03cb8c
+size 16788258
diff --git a/pkg/rudus_bg.wasm.d.ts b/pkg/rudus_bg.wasm.d.ts
index 2186b19..e654bfa 100644
--- a/pkg/rudus_bg.wasm.d.ts
+++ b/pkg/rudus_bg.wasm.d.ts
@@ -6,9 +6,9 @@ export const __wbindgen_exn_store: (a: number) => void;
 export const __externref_table_alloc: () => number;
 export const __wbindgen_export_2: WebAssembly.Table;
 export const __wbindgen_free: (a: number, b: number, c: number) => void;
-export const __wbindgen_export_4: WebAssembly.Table;
 export const __wbindgen_malloc: (a: number, b: number) => number;
 export const __wbindgen_realloc: (a: number, b: number, c: number, d: number) => number;
-export const closure354_externref_shim: (a: number, b: number, c: any) => void;
-export const closure377_externref_shim: (a: number, b: number, c: any, d: any) => void;
+export const __wbindgen_export_6: WebAssembly.Table;
+export const closure361_externref_shim: (a: number, b: number, c: any) => void;
+export const closure384_externref_shim: (a: number, b: number, c: any, d: any) => void;
 export const __wbindgen_start: () => void;
diff --git a/pkg/turtle_geometry.js b/pkg/turtle_geometry.js
index b9931cf..0140f77 100644
--- a/pkg/turtle_geometry.js
+++ b/pkg/turtle_geometry.js
@@ -72,52 +72,52 @@ export function command_to_state (prev_state, curr_command) {
   switch (verb) {
     case "goto": {
       const [_, [x, y]] = curr_command
-      return {...prev_state, position: [x, y]}
+      return {...prev_state, position: [x, y], clear: false}
     }
     case "home": {
-      return {...prev_state, position: [0, 0], heading: 0}
+      return {...prev_state, position: [0, 0], heading: 0, clear: false}
     }
     case "right": {
       const [_, angle] = curr_command
       const {heading} = prev_state
-      return {...prev_state, heading: heading + angle}
+      return {...prev_state, heading: heading + angle, clear: false}
     }
     case "left": {
       const [_, angle] = curr_command
       const {heading} = prev_state
-      return {...prev_state, heading: heading - angle}
+      return {...prev_state, heading: heading - angle, clear: false}
     }
     case "forward": {
       const [_, steps] = curr_command
       const {heading, position} = prev_state
       const unit = unit_of(heading)
       const move = mult(unit, steps)
-      return {...prev_state, position: add(position, move)}
+      return {...prev_state, position: add(position, move), clear: false}
     }
     case "back": {
       const [_, steps] = curr_command
       const {heading, position} = prev_state
       const unit = unit_of(heading)
       const move = mult(unit, -steps)
-      return {...prev_state, position: add(position, move)}
+      return {...prev_state, position: add(position, move), clear: false}
     }
     case "penup": {
-      return {...prev_state, pendown: false}
+      return {...prev_state, pendown: false, clear: false}
     }
     case "pendown": {
-      return {...prev_state, pendown: true}
+      return {...prev_state, pendown: true, clear: false}
     }
     case "penwidth": {
       const [_, width] = curr_command
-      return {...prev_state, penwidth: width}
+      return {...prev_state, penwidth: width, clear: false}
     }
     case "pencolor": {
       const [_, color] = curr_command
-      return {...prev_state, pencolor: color}
+      return {...prev_state, pencolor: color, clear: false}
     }
     case "setheading": {
       const [_, heading] = curr_command
-      return {...prev_state, heading: heading}
+      return {...prev_state, heading: heading, clear: false}
     }
     case "loadstate": {
       // console.log("LOADSTATE: ", curr_command)
@@ -125,15 +125,18 @@ export function command_to_state (prev_state, curr_command) {
       return {position: [x, y], heading, visible, pendown, penwidth, pencolor}
     }
     case "show": {
-      return {...prev_state, visible: true}
+      return {...prev_state, visible: true, clear: false}
     }
     case "hide": {
-      return {...prev_state, visible: false}
+      return {...prev_state, visible: false, clear: false}
     }
     case "background": {
       background_color = curr_command[1]
       return prev_state
     }
+    case "clear": {
+      return {...prev_state, clear: true}
+    }
   }
 }
 
diff --git a/src/lib.rs b/src/lib.rs
index c9955b7..0605ed6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -111,7 +111,7 @@ fn prelude() -> HashMap<Key, Value> {
 #[wasm_bindgen]
 pub async fn ludus(src: String) {
     // instrument wasm to report rust panics
-    // console_error_panic_hook::set_once();
+    console_error_panic_hook::set_once();
     // leak the source so it lives FOREVER
     let src = src.to_string().leak();