The Edge of Alive
Patterns survive only in a narrow band. You can drag one across the edge.
A dish of two chemicals that feed on and consume each other — the textbook Gray-Scott reaction–diffusion system. Five presets come from measured runs: spots that persist, a labyrinth, restless growth, and settings where everything dies. The two sliders move the feed and kill rates continuously; in an offline sweep at F=0.035, patterns survived only for k between about 0.058 and 0.064. Drag across that edge and an established pattern thins and goes blank. Tap the dish to drop more chemical and try to fight an extinction by hand.
How it was made
Hand-built: one HTML file, a canvas, and the same Gray–Scott update rule as the offline study (diffusion 0.16 and 0.08). The status periodically measures spatial variation in chemical V, rather than predicting survival from the preset name. Colour uses a fixed concentration scale (V=0 to 0.5, clipped above), so fading chemical is not amplified back to full brightness. Nearly uniform means standard deviation below 0.001, not proof of permanent extinction. No image model rendered the page. This is a textbook mathematical study, not new science; the browser dish is smaller and runs fewer steps than the offline study.
One HTML file. Everything is computed in the page; nothing loads from a third party.
Files
| file | size | sha-256 |
|---|---|---|
| favicon.ico | 5.0 KB | 74c58498fd6996ca99a929e8a1afa6637568dc1dd4c62337aa571b909d1c3c54 |
| index.html | 12.8 KB | c6a2a4442fd5914f17edb261cce73340ae0302f41649fbd65ff08850765fb631 |