> Create a single self-contained index.html: a ~2-minute animated piano performance in a hand-drawn crayon style. > Scene: a cozy room at night, an upright piano, a small black cat playing it. Crayon texture on every surface: grainy strokes,wobbly outlines, paper tooth. > Music: compose an original piano piece (~40 bars, clear melody, calm then building, soft ending). Synthesize the piano in Web Audio with harmonics, hammer noise and reverb. No audio files. > Sync: one timeline drives both. The cat's paws hit the keys that are actually sounding. Lights, camera and mood follow the music. > Rules: Canvas 2D only, no libraries, no external assets. Support pause/replay and ?t=90 to jump to any moment.
Make it yours. Swap the scene ("a small black cat playing it"), the medium ("hand-drawn crayon style", "Crayon texture on every surface"), and the music line ("~40 bars, clear melody, calm then building, soft ending"). Keep the "Sync:" and "Rules:" lines; they hold picture and sound to one timeline.
Crayon piano performance with a black cat
An 85-second crayon-textured scene of an upright piano played by a small coral character while a black cat watches from on top, as day turns to night. Opus 5.5 composed the 41-bar piece and synthesized the piano in Web Audio, all in one index.html.
“no After Effects. no stock music. no assets.”
You'll need
- A browser to run the page, plus a screen recorder or frame capture to turn it into a video file
How it was made
Per the creator: 657 notes across 41 bars, composed by Opus; the piano synthesized live in Web Audio with harmonics, hammer noise, and reverb; one clock driving picture and sound; everything in one index.html with zero dependencies. The posted video differs from the prompt in two ways: a small coral character plays while the black cat lies on top of the piano, though the prompt asks for the cat to play; and it runs 85 seconds rather than about 2 minutes. The creator doesn't say whether there were follow-up prompts. They say they made it after reading @0xMovez's X article on motion design with Opus 5.5.
Posted Sep 27, 2026 · X · 48 likes · 7.2k views · 7 comments
Prompt from: Post body, each paragraph quoted with ">"
Look notesby Reference
A crayon-drawn living room seen straight on: a pale blue upright piano, a small coral block character playing it, and a black cat lying on top, while glowing notes rise from the keys and the window turns from day to night.
- Color
- Chalky pastels with grainy crayon strokes: a powder-blue piano, a coral-red player and rug, cream wallpaper, and lamp-yellow light, with the window sky moving from pale blue through orange dusk to deep indigo. The notes glow green, yellow, and blue.
- Type
- No titles. Hand-drawn notation on the sheet music, with chord names such as Em and B7.
- Framing
- A fixed, centered frontal view: the piano fills most of the frame, a floor lamp stands at left, the curtained window at right, and the player's bench is centered over an oval rug. Shafts of light rise from the keys being pressed.
- Sound
- An original piano piece of 657 notes over 41 bars, composed by Opus and synthesized live in Web Audio with harmonics, hammer noise, and reverb, according to the creator.
- Structure
- One room throughout: daylight with clouds outside, then sunset, then a moonlit night, as the lamps and candle glow brighter and the cat opens its green eyes. In the last frame the player's eyes are squeezed shut.
