Coral Growth

Watch Coral Growth live in the browser

A branching coral grows out of a seed in dark blue water. Fresh tips glow, older growth settles into bands of rose, coral, sand, sea-glass teal and violet, and after a while the whole reef pales, crumbles away and a new one starts.

This is diffusion-limited aggregation, described by Witten and Sander in 1981. Particles wander at random until they touch the coral and stick. A wandering particle is far more likely to hit a tip than to reach deep into a gap, so tips outgrow everything else and the coral branches into a fractal. Here real random walkers move on a 320 by 180 grid, and each new piece is coloured by when it grew and by the pitch of the music at that moment.

What it reacts to

• Overall loudness: sets how fast the walkers move and the coral grows; in silence the reef freezes
• Pitch balance (spectral centroid): colours each newly grown ring, so the reef records the track
• Treble: fresh tips glow brighter
• Kick drum: a soft flash, and now and then a new seed planted somewhere else

Tune

Growth speed scales the pace, Stickiness trades thin fern-like branches for dense bushy coral, and Coral lifetime sets how long a reef lives before it crumbles.

Music that suits it

Long tracks that change in timbre, such as progressive electronic music, post-rock or orchestral pieces, leave visible growth rings of different colours.

How to play it

Install Deus, play music on Spotify, YouTube Music, Yandex Music or any other tab and click the Deus icon on that tab. Then pick Coral Growth in the WebGL presets, or press ← → on the page until it comes up.