Indirectly via @robsimonsen! From the SoundManager2 site. Pretty solid breakdown of concept and build here. If you’re a cool kid with fast internet, make sure to enjoy Scratch Mode! See my collection of other audiotoy posts here.

It’s also available in the AppStore for your iDevice.
Kind of like Tonematrix, but different…
Each alive cell has 4 states: Up, right, down, left. at each cycle, the cells move themselves in the direction of their internal states. If any cell encounters a wall, it triggers a pitched sound whose frequency is determined by the xy position of collision, and the cell reverses its direction. If a cell encounters another cell on its way, it turns itself clockwise.
This set of rules produces chaotic results in some settings, therefore you can end up with never repeating, gradually evolving sequences.—via earslap
The creative/graphics and execution on this is BEAUTIFUL. The UI/UX is incredible. Well done. Burn Studio’s Audiotool, codename, Hitchhiker.
Um, can there be an OS X desktop version pleaaaase??? My bandwidth SUCKS!
Also see previous web based audio toy posts:
Tonematrix (by Andre Michelle, one of the people on the Audiotool team)
Also found on this blog.
For an introduction video (and where I came across the link) check here.