diff --git a/webserial/src/editor/Monaco.svelte b/webserial/src/editor/Monaco.svelte
index f19343f..13307da 100644
--- a/webserial/src/editor/Monaco.svelte
+++ b/webserial/src/editor/Monaco.svelte
@@ -7,12 +7,13 @@
     import defaultCode from "./defaultCode.ts?raw";
     import defaultEnv from "./defaultEnv.d.ts?raw";
     import { code } from "./code";
+    import tsOptions from "../eval/tsOptions";
 
     let divEl: HTMLDivElement = null;
     let editor: monaco.editor.IStandaloneCodeEditor;
 
     let value = defaultCode;
-    $: $code = TS.transpile(value, { strict: true });
+    $: $code = TS.transpile(value, tsOptions);
 
     onMount(async () => {
         // @ts-ignore
@@ -30,7 +31,10 @@
             language: "typescript",
         });
 
-        let lib = monaco.languages.typescript.typescriptDefaults.addExtraLib(defaultEnv);
+        let lib =
+            monaco.languages.typescript.typescriptDefaults.addExtraLib(
+                defaultEnv
+            );
 
         editor.onKeyUp((_e) => (value = editor.getValue()));
 
diff --git a/webserial/src/editor/code.ts b/webserial/src/editor/code.ts
index 2b329af..d8f486c 100644
--- a/webserial/src/editor/code.ts
+++ b/webserial/src/editor/code.ts
@@ -1,6 +1,7 @@
 import { writable } from "svelte/store";
 import defaultCode from "./defaultCode.ts?raw";
 import TS from "typescript";
+import tsOptions from "../eval/tsOptions";
 
 /** the transpiled JavaScript code */
-export const code = writable(TS.transpile(defaultCode, {strict: true}));
\ No newline at end of file
+export const code = writable(TS.transpile(defaultCode, tsOptions));
\ No newline at end of file
diff --git a/webserial/src/editor/defaultCode.ts b/webserial/src/editor/defaultCode.ts
index 9c5bd09..ed40918 100644
--- a/webserial/src/editor/defaultCode.ts
+++ b/webserial/src/editor/defaultCode.ts
@@ -1,4 +1,101 @@
-// ayaya ayaya
+// Connect the interface with the button below and modify the code here.
+// The output should update in real time as you type :)
 
-ctx.set(1, 255);
-ctx.set(2, 255);
\ No newline at end of file
+// Fixtures library. TODO move this into a separate file
+
+class Fixture {
+    address: number
+    ctx: Context
+
+    constructor(address: number, ctx: Context) {
+        this.address = address;
+        this.ctx = ctx;
+    }
+}
+
+interface GenericRGBW {
+    /**
+     * Set the brightness
+     * 
+     * @param value between 0 and 1
+     * @param strobe enable strobe (turn off if unsupported)
+     */
+    setBrightness(value: number, strobe?: boolean): void
+    setRGBW(rgb: [number, number, number], w?: number): void
+}
+
+class Par extends Fixture implements GenericRGBW {
+    setBrightness(value: number, strobe?: boolean) {
+        if (strobe || false) {
+            this.ctx.set(this.address, 255);
+            this.ctx.set(this.address + 7, value * 255);
+        } else {
+            this.ctx.set(this.address, value * 255);
+            this.ctx.set(this.address + 7, 0);
+        }
+    }
+
+    setRGBW(rgb: [number, number, number], w?: number) {
+        let [r, g, b] = rgb;
+        this.ctx.set(this.address + 1, r);
+        this.ctx.set(this.address + 2, g);
+        this.ctx.set(this.address + 3, b);
+        this.ctx.set(this.address + 4, w || 0);
+    }
+
+    setAUV(a: number, uv: number) {
+        this.ctx.set(this.address + 5, a);
+        this.ctx.set(this.address + 6, uv);
+    }
+}
+
+class MovingHead extends Fixture implements GenericRGBW {
+    setBrightness(value: number, strobe?: boolean) {
+        let out = (strobe || false)
+            ? 135 + (239 - 135) * value
+            : 8 + (134 - 8) * value;
+        this.ctx.set(this.address + 5, out);
+    }
+
+    setRGBW(rgb: [number, number, number], w?: number) {
+        let [r, g, b] = rgb;
+        this.ctx.set(this.address + 6, r);
+        this.ctx.set(this.address + 7, g);
+        this.ctx.set(this.address + 8, b);
+        this.ctx.set(this.address + 9, w || 0);
+    }
+
+    /**
+     * Rotate the moving head. Pan and tilt are in radians.
+     * @param pan between -1.5pi and 1.5pi
+     * @param tilt between -0.5pi and 0.5pi
+     * @param speed between 0 (fast) and 255 (slow)
+     */
+    setPanTilt(pan: number, tilt: number, speed?: number) {
+        let panRough = (pan + 3 * Math.PI / 2) / (Math.PI * 3) * 256
+        panRough = Math.max(0, Math.min(255, panRough))
+
+        let tiltRough = (tilt + Math.PI / 2) / (Math.PI) * 256
+        tiltRough = Math.max(0, Math.min(255, tiltRough))
+
+        // TODO
+        let panFine = 0
+        let tiltFine = 0
+
+        this.ctx.set(this.address + 0, panRough);
+        this.ctx.set(this.address + 1, panFine);
+        this.ctx.set(this.address + 2, tiltRough);
+        this.ctx.set(this.address + 3, tiltFine);
+        this.ctx.set(this.address + 4, speed || 0);
+    }
+}
+
+// ******************
+// * CODE GOES HERE *
+// ******************
+
+let color = lib.hsl2rgb(360 * t, 100, 50);
+
+let par = new Par(1, ctx);
+par.setBrightness(1);
+par.setRGBW(color);
\ No newline at end of file
diff --git a/webserial/src/editor/defaultEnv.d.ts b/webserial/src/editor/defaultEnv.d.ts
index 1d43a76..9d7cbfd 100644
--- a/webserial/src/editor/defaultEnv.d.ts
+++ b/webserial/src/editor/defaultEnv.d.ts
@@ -1,9 +1,30 @@
 type Context = {
+    /**
+     * Set DMX address `address` to `value`
+     * @param address between 1 and 511
+     * @param value between 0 and 255
+     */
     set(address: number, value: number): void,
 };
 
-/** the global Context object */
+/** The global Context object */
 declare const ctx: Context;
 
-/** the current time (in seconds, e.g. 1.25 after 1250 milliseconds) */
-declare const t: number;
\ No newline at end of file
+/** The current time (in seconds, e.g. 1.25 after 1250 milliseconds) */
+declare const t: number;
+
+type Lib = {
+    /**
+    * Converts from the HSL color space to RGB
+    * 
+    * Outputs [r, g, b] between 0 and 255 each
+    * 
+    * @param h in degrees, i.e. 0 to 360
+    * @param s between 0 and 100
+    * @param l between 0 and 100
+    */
+    hsl2rgb(h: number, s: number, l: number): [number, number, number]
+}
+
+/** The standard library */
+declare const lib: Lib;
\ No newline at end of file
diff --git a/webserial/src/eval/EvalLoop.svelte b/webserial/src/eval/EvalLoop.svelte
index bedba0d..b902bd3 100644
--- a/webserial/src/eval/EvalLoop.svelte
+++ b/webserial/src/eval/EvalLoop.svelte
@@ -3,14 +3,16 @@
     import { onMount } from "svelte";
     import { code } from "../editor/code";
     import { dmxData } from "../dmx/store";
+    import { lib } from "./lib";
 
     let startTime: number;
     let payload = new Uint8Array(512);
     let ctx: Context = {
         set(address: number, value: number) {
-            payload[address - 1] = value;
-        }
-    }
+            let rounded = Math.round(value);
+            payload[address - 1] = Math.max(0, Math.min(255, rounded));
+        },
+    };
 
     let result: string;
 
@@ -18,7 +20,7 @@
         payload = new Uint8Array(512);
         const t = (performance.now() - startTime) / 1000;
         try {
-            let ret = Function("ctx", "t", $code).call({}, ctx, t);
+            let ret = Function("ctx", "t", "lib", $code).call({}, ctx, t, lib);
             result = JSON.stringify(ret);
         } catch (err) {
             result = JSON.stringify(err);
@@ -36,8 +38,8 @@
 
         return () => {
             clearInterval(int);
-        }
-    })
+        };
+    });
 </script>
 
-<!-- <pre>{result}</pre> -->
\ No newline at end of file
+<!-- <pre>{result}</pre> -->
diff --git a/webserial/src/eval/lib.ts b/webserial/src/eval/lib.ts
new file mode 100644
index 0000000..6f1f18b
--- /dev/null
+++ b/webserial/src/eval/lib.ts
@@ -0,0 +1,16 @@
+/// <reference path="../editor/defaultEnv.d.ts" />
+
+export const lib: Lib = {
+    hsl2rgb(h, s, l): [number, number, number] {
+        // https://stackoverflow.com/a/44134328
+        l /= 100;
+        const a = s * Math.min(l, 1 - l) / 100;
+        const f = n => {
+            const k = (n + h / 30) % 12;
+            const color = l - a * Math.max(Math.min(k - 3, 9 - k, 1), -1);
+            return Math.round(255 * color)
+        };
+        return [f(0), f(8), f(4)];
+
+    },
+}
\ No newline at end of file
diff --git a/webserial/src/eval/tsOptions.ts b/webserial/src/eval/tsOptions.ts
new file mode 100644
index 0000000..a3c073e
--- /dev/null
+++ b/webserial/src/eval/tsOptions.ts
@@ -0,0 +1,7 @@
+import type { CompilerOptions } from "typescript"
+
+const tsOptions: CompilerOptions = {
+    strict: true
+}
+
+export default tsOptions
\ No newline at end of file
diff --git a/webserial/src/serial/SerialConnection.svelte b/webserial/src/serial/SerialConnection.svelte
index 6e8f1bf..a90309a 100644
--- a/webserial/src/serial/SerialConnection.svelte
+++ b/webserial/src/serial/SerialConnection.svelte
@@ -98,7 +98,11 @@
             if (loopTime < FRAME_TIME) {
                 await sleep(FRAME_TIME - loopTime);
             } else {
-                console.warn(`loop took too long (+${(loopTime - FRAME_TIME).toFixed(2)} ms)`);
+                console.warn(
+                    `loop took too long (+${(loopTime - FRAME_TIME).toFixed(
+                        2
+                    )} ms)`
+                );
             }
             lastLoopTime = loopTime;
         }
diff --git a/webserial/src/serial/SerialManager.svelte b/webserial/src/serial/SerialManager.svelte
index 7ed2812..360737c 100644
--- a/webserial/src/serial/SerialManager.svelte
+++ b/webserial/src/serial/SerialManager.svelte
@@ -14,22 +14,27 @@
 </script>
 
 <div>
-{#if navigator.serial}
-    <p>Serial available &#x1f680;</p>
-    {#if port !== null}
-        <SerialConnection {port}/>
-        <p><button on:click={disconnect}>disconnect</button></p>
+    {#if navigator.serial}
+        <p>Serial available &#x1f680;</p>
+        {#if port !== null}
+            <SerialConnection {port} />
+            <p><button on:click={disconnect}>disconnect</button></p>
+        {:else}
+            <p><button on:click={connect}>connect</button></p>
+        {/if}
     {:else}
-        <p><button on:click={connect}>connect</button></p>
+        <p>Looks like your browser does not support WebSerial &#x1f622;</p>
+        <p>
+            Check <a
+                href="https://developer.mozilla.org/en-US/docs/Web/API/Web_Serial_API#browser_compatibility"
+                >here</a
+            > for a list of compatible browsers
+        </p>
     {/if}
-{:else}
-    <p>Looks like your browser does not support WebSerial &#x1f622;</p>
-    <p>Check <a href="https://developer.mozilla.org/en-US/docs/Web/API/Web_Serial_API#browser_compatibility">here</a> for a list of compatible browsers</p>
-{/if}
 </div>
 
 <style lang="scss">
     div {
         height: 15vh;
     }
-</style>
\ No newline at end of file
+</style>