diff --git a/repl/public/global.css b/repl/public/global.css
index a0a08e22..469626bd 100644
--- a/repl/public/global.css
+++ b/repl/public/global.css
@@ -14,5 +14,17 @@ body {
 }
 
 .CodeMirror-line > span {
-  background-color: #2a323690;
+  background-color: #2a323699;
+}
+
+.darken::before {
+  content: ' ';
+  position: absolute;
+  top: 0;
+  left: 0;
+  width: 100vw;
+  height: 100vh;
+  display: block;
+  background: black;
+  opacity: 0.5;
 }
diff --git a/repl/src/App.tsx b/repl/src/App.tsx
index aaae4e75..17956cda 100644
--- a/repl/src/App.tsx
+++ b/repl/src/App.tsx
@@ -83,6 +83,7 @@ function App() {
   return (
     <div className="min-h-screen flex flex-col">
       <header
+        id="header"
         className={cx(
           'flex-none w-full h-14 px-2 flex border-b border-gray-200  justify-between z-[10]',
           uiHidden ? 'bg-transparent text-white' : 'bg-white'
@@ -138,7 +139,7 @@ function App() {
         </div>
       </header>
       <section className="grow flex flex-col text-gray-100">
-        <div className="grow relative">
+        <div className="grow relative" id="code">
           <div
             className={cx(
               'h-full transition-opacity',
diff --git a/repl/src/CodeMirror.tsx b/repl/src/CodeMirror.tsx
index 9ee18798..6f67b669 100644
--- a/repl/src/CodeMirror.tsx
+++ b/repl/src/CodeMirror.tsx
@@ -36,7 +36,7 @@ export const markEvent = (editor) => (time, event) => {
       { line: start.line - 1, ch: start.column },
       { line: end.line - 1, ch: end.column },
       //{ css: 'background-color: #FFCA28; color: black' } // background-color is now used by parent marking
-      { css: 'outline: 1px solid #FFCA28; box-sizing:border-box' }
+      { css: 'outline: 2px solid #FFCA28; box-sizing:border-box' }
     )
   );
   //Tone.Transport.schedule(() => { // problem: this can be cleared by scheduler...
@@ -51,7 +51,7 @@ export const markParens = (editor, data) => {
   const v = editor.getDoc().getValue();
   const marked = getCurrentParenArea(v, data);
   parenMark?.clear();
-  parenMark = editor.getDoc().markText(...marked, { css: 'background-color: #00000020' }); //
+  parenMark = editor.getDoc().markText(...marked, { css: 'background-color: #0000dd20' }); //
 };
 
 // returns { line, ch } from absolute character offset
diff --git a/repl/src/evaluate.ts b/repl/src/evaluate.ts
index 546433c1..dc59383f 100644
--- a/repl/src/evaluate.ts
+++ b/repl/src/evaluate.ts
@@ -8,6 +8,7 @@ import './tune.mjs';
 import './tune.mjs';
 import './pianoroll.mjs';
 import './draw.mjs';
+import * as uiHelpers from './ui.mjs';
 import * as drawHelpers from './draw.mjs';
 import gist from './gist.js';
 import shapeshifter from './shapeshifter';
@@ -35,7 +36,7 @@ hackLiteral(String, ['mini', 'm'], bootstrapped.mini); // comment out this line
 hackLiteral(String, ['pure', 'p'], bootstrapped.pure); // comment out this line if you panic
 
 // this will add everything to global scope, which is accessed by eval
-Object.assign(globalThis, bootstrapped, Tone, toneHelpers, voicingHelpers, drawHelpers, { gist });
+Object.assign(globalThis, bootstrapped, Tone, toneHelpers, voicingHelpers, drawHelpers, uiHelpers, { gist });
 
 export const evaluate: any = async (code: string) => {
   const shapeshifted = shapeshifter(code); // transform syntactically correct js code to semantically usable code
diff --git a/repl/src/ui.mjs b/repl/src/ui.mjs
new file mode 100644
index 00000000..b95dc764
--- /dev/null
+++ b/repl/src/ui.mjs
@@ -0,0 +1,42 @@
+import * as Tone from 'tone';
+
+export const hideHeader = () => {
+  document.getElementById('header').style = 'display:none';
+};
+
+function frame(callback) {
+  if (window.strudelAnimation) {
+    cancelAnimationFrame(window.strudelAnimation);
+  }
+  const animate = (animationTime) => {
+    const toneTime = Tone.getTransport().seconds;
+    callback(animationTime, toneTime);
+    window.strudelAnimation = requestAnimationFrame(animate);
+  };
+  requestAnimationFrame(animate);
+}
+
+export const backgroundImage = function (src, animateOptions) {
+  const container = document.getElementById('code');
+  const bg = 'background-image:url(' + src + ');background-size:contain;';
+  container.style = bg;
+  const { className: initialClassName } = container;
+  const handleOption = (option, value) => {
+    ({
+      style: () => (container.style = bg + ';' + value),
+      className: () => (container.className = value + ' ' + initialClassName),
+    }[option]());
+  };
+  const funcOptions = Object.entries(animateOptions).filter(([_, v]) => typeof v === 'function');
+  const stringOptions = Object.entries(animateOptions).filter(([_, v]) => typeof v === 'string');
+  stringOptions.forEach(([option, value]) => handleOption(option, value));
+
+  if (funcOptions.length === 0) {
+    return;
+  }
+  frame((_, t) =>
+    funcOptions.forEach(([option, value]) => {
+      handleOption(option, value(t));
+    })
+  );
+};