diff --git a/demo/beats.html b/demo/beats.html
new file mode 100644
index 0000000..a0498b0
--- /dev/null
+++ b/demo/beats.html
@@ -0,0 +1,74 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Beats</title>
+    <style>
+      html {
+        height: 100%;
+      }
+
+      body {
+        min-height: 100%;
+        position: relative;
+        margin: 0;
+      }
+
+      event-propagator {
+        display: block;
+        position: absolute;
+        inset: 0 0 0 0;
+        pointer-events: none;
+      }
+
+      fc-geometry {
+        border: 1px solid black;
+        border-radius: 4px;
+      }
+
+      folk-metronome {
+        padding: 0.5rem;
+      }
+    </style>
+  </head>
+  <body>
+    <fc-geometry x="100" y="100">
+      <folk-metronome bpm="120"></folk-metronome>
+    </fc-geometry>
+
+    <fc-geometry x="200" y="100">
+      <audio id="kick" src="/Kick_Bouncy.wav" controls></audio>
+    </fc-geometry>
+
+    <fc-geometry x="200" y="200">
+      <audio id="hat" src="/Hat_Closed.wav" controls></audio>
+    </fc-geometry>
+
+    <event-propagator
+      source="folk-metronome"
+      target="#kick"
+      triggers="beat"
+      expression="if ($source.beat % 2 === 0) $target.play();"
+    ></event-propagator>
+
+    <event-propagator
+      source="folk-metronome"
+      target="#hat"
+      triggers="beat"
+      expression="if ($source.beat > 2) $target.play();"
+    ></event-propagator>
+
+    <script type="module">
+      import { FolkGeometry } from '../src/canvas/fc-geometry.ts';
+      import { FolkLLM } from '../src/folk-llm.ts';
+      import { FolkMetronome } from '../src/folk-metronome.ts';
+      import { EventPropagator } from '../src/arrows/event-propagator.ts';
+
+      FolkGeometry.register();
+      FolkLLM.register();
+      FolkMetronome.register();
+      EventPropagator.register();
+    </script>
+  </body>
+</html>
diff --git a/demo/music.html b/demo/proximity-music.html
similarity index 99%
rename from demo/music.html
rename to demo/proximity-music.html
index 1334c74..ab7b8f6 100644
--- a/demo/music.html
+++ b/demo/proximity-music.html
@@ -3,7 +3,7 @@
   <head>
     <meta charset="UTF-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-    <title>Music</title>
+    <title>Proximity Music</title>
     <style>
       html {
         height: 100%;
diff --git a/demo/public/Hat_Closed.wav b/demo/public/Hat_Closed.wav
new file mode 100644
index 0000000..ae2cd91
Binary files /dev/null and b/demo/public/Hat_Closed.wav differ
diff --git a/demo/public/Kick_Bouncy.wav b/demo/public/Kick_Bouncy.wav
new file mode 100644
index 0000000..e8dcd4d
Binary files /dev/null and b/demo/public/Kick_Bouncy.wav differ
diff --git a/src/folk-metronome.ts b/src/folk-metronome.ts
new file mode 100644
index 0000000..31786ae
--- /dev/null
+++ b/src/folk-metronome.ts
@@ -0,0 +1,71 @@
+declare global {
+  interface HTMLElementTagNameMap {
+    'folk-metronome': FolkMetronome;
+  }
+}
+
+export class FolkMetronome extends HTMLElement {
+  static tagName = 'folk-metronome';
+
+  static register() {
+    customElements.define(this.tagName, this);
+  }
+
+  constructor() {
+    super();
+
+    this.addEventListener('click', this);
+  }
+
+  #timeoutId = -1;
+
+  get isPlaying() {
+    return this.#timeoutId !== -1;
+  }
+
+  // default to 100ms per beat
+  #bpm = Number(this.getAttribute('bpm') || 100);
+  get bpm() {
+    return this.#bpm;
+  }
+  set bpm(bpm) {
+    this.#bpm = bpm;
+  }
+
+  #beat = 0;
+  get beat() {
+    return this.#beat;
+  }
+
+  get #intervalMs() {
+    return (60 * 1000) / this.#bpm;
+  }
+
+  handleEvent(e) {
+    if (e.type === 'click' && e.target === this) {
+      this.isPlaying ? this.pause() : this.play();
+    }
+  }
+
+  play() {
+    this.#timeoutId = setInterval(() => {
+      this.#updateBeat(this.#beat + 1);
+      this.dispatchEvent(new Event('beat'));
+    }, this.#intervalMs);
+  }
+
+  pause() {
+    clearInterval(this.#timeoutId);
+    this.#timeoutId = -1;
+  }
+
+  reset() {
+    this.pause();
+    this.#updateBeat(0);
+  }
+
+  #updateBeat = (nextBeat: number) => {
+    this.#beat = ((nextBeat - 1) % 4) + 1;
+    this.textContent = this.#beat.toString();
+  };
+}
