Video & animationModel: Claude Opus 5.5Effort: maxRuns in: Claude Code

Recursion explained in nine film styles

Watch a 60-second demonstration of recursion in nine film styles, from film noir to pixel art. The prompt and the text in the film are in English.

Published October 19, 2026

Silent excerpt

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Prompt

Make a 60-second explainer film about recursion, and make the film itself recursive.

THE IDEA
- Treat the film as a function, explain(n). It starts at n = 9 and calls itself with n - 1 until it reaches n = 0.
- Every call is a scene in a completely different film genre, for example film noir, wildlife documentary, 8-bit platformer, VHS horror, late-night infomercial, comic book, ink painting, movie trailer and a code editor.
- The next scene always lives inside an object in the current one: a photograph, a dew drop, a TV screen, a box, a comic panel. The camera dives into it, and that dive is the recursive call. Show the current n somewhere natural in each scene: a case number, a level, a channel.
- Each scene teaches one idea and builds on the one before: a function that calls itself, a smaller problem each time, the base case, what happens without one, the call stack, answers coming back up, one call branching into two, trusting the smaller call, and finally the film reaching its own base case.
- Open with a one-sentence hook. At n = 0, return: pull the camera back out through every scene in reverse order, let each one hand back a single word, and land on one sentence that sums up the whole idea.

CRAFT
- Give every genre its own typeface, colours, pacing, motion and music. No shared overlay or filter that makes the scenes look alike.
- One idea per scene. Every line must be readable before the next scene starts.
- Do not use crossfades between scenes, decorative gradients or glows, any shot that stands still for more than a second, or anything that feels like a template.

BUILD
1. Write everything as one HTML file at 1920x1080 that exposes window.seek(t). Every pixel must be a pure function of t: no CSS animations, timers, randomness or state kept between frames.
2. Animate with springs and exponential easing written as functions of time. Fast movement gets motion blur along its direction and speed.
3. Compose the soundtrack in code with an OfflineAudioContext: music that changes with each genre, a short sting at every scene change, and the next scene's music heard faintly through its frame before the camera enters it. Export it as a WAV file.
4. Render with Playwright at 60 fps, three sub-frames per frame blended with ffmpeg tmix, then mux the audio into an MP4.
5. Before the full render, export one frame per musical beat and review them. Fix anything crowded, off the beat, overlapping or hard to read.

Start by listing the nine scenes with their idea, genre and the object the camera dives into. Then build everything without asking questions, and deliver the final MP4 plus a 10-second excerpt.

What you need

Node.js and npm
Playwright with Chromium
ffmpeg
A local working folder for HTML, audio and video

About the prompt

Recommended local setup: Claude Code with Claude Opus 5.5 and effort set to Max. These are the settings we recommend for running the prompt with local tools.

A film that calls itself

The demonstration runs for one minute. The camera enters an object in each scene and finds the next, smaller explanation inside it. The film follows the idea of explain(n): reduce the problem, reach the base case at n = 0, then return through the calls in reverse order.

Nine visual explanations

Film noir: a function that calls itself.
Nature documentary: the same structure in progressively smaller parts.
Pixel game: a base case that returns an answer and stops further calls.
VHS horror: what happens without a stopping condition.
Infomercial: the call stack keeps track of functions waiting for an answer.
Comic book: answers return, and each call completes its part.
Ink painting: one call can branch into two.
Movie trailer: trust the smaller call to solve its part.
Code editor: the base case is reached before the film returns through the scenes.

From HTML to a video file

The approach uses one 1920 × 1080 HTML file with window.seek(t), so each frame can be calculated from its timestamp. Web Audio creates music and sound effects. Playwright renders the frames, while ffmpeg assembles the video and audio. The target is 60 frames per second, with three subframes per frame for motion blur.

Language and expectations

The prompt and the text in the film are in English. This is a demonstration of one possible visual result, not a guarantee of an identical output. The model, available fonts, tools and revisions can affect the outcome. Check the content, readability and audio before sharing your version.

How to use the prompt

How to get the same kind of result as the demo.

1
Watch the demonstration
Watch the full film and notice the transition into each scene, the stopping condition and the return journey. Pause when you need more time to read an explanation. The text in the film is in English.
2
Prepare a separate working folder
Make sure Node.js with npm, Playwright with Chromium and ffmpeg are installed. Use a separate folder with room for HTML, WAV, intermediate frames and the final video. Rendering may require substantial time and disk space.
3
Copy the entire prompt
Keep the structure, requirements and numbered instructions. Use the documented setup on this page when available. Pasting the text alone does not install tools or start a local render.
4
Review the scenes and still frames
Review the plan for all nine styles. Check one frame per musical beat before rendering the full film. Request corrections to text that overlaps, is hard to read or disappears too quickly.
5
Render the video and soundtrack
Check that window.seek(t) works in the HTML file. Export the soundtrack to WAV, render at 60 frames per second and combine video and audio with ffmpeg. Use the prompt’s three subframes per frame when supported by the rendering setup.
6
Test and refine the result
Play the entire export and check its duration, readability and audio synchronisation. Create a silent 10-second excerpt for previewing. Results can vary; request specific improvements instead of expecting an identical copy.

Prompt

What you need

About the prompt

A film that calls itself

Nine visual explanations

From HTML to a video file

Language and expectations

How to use the prompt

Watch the demonstration

Prepare a separate working folder

Copy the entire prompt

Review the scenes and still frames

Render the video and soundtrack

Test and refine the result