Frame-Deterministic Butterfly Animation

An X-ray butterfly demonstration of the "each frame depends only on frame number" method for code video: fixed canvas, windowless engine calls draw(f) per frame, ffmpeg encoding, then three automated verification passes. Sample loops 720 frames, 12 seconds; frame 0 and frame 720 are pixel-identical. Ideal for technical method explanation, animation workflow sharing, and developer-focused short-form education.