One thing that I really like is the way you can see the waves reflecting off the walls. Sure, this isn’t exactly the most spectacular example of emergent behaviour, but it’s certainly not explicitly coded in. I think that’s pretty neat.

Don’t forget to play with keys 1,2,3,4,5, and all the other keys listed in the red help text. One unlisted function is that holding the shift key allows you to press, rather than lift the pixels.

For you nerds, yes, it’s a 2d array of elements connected to their neighbours by “springs”. Short story: each pixel accelerates toward the average of its neighbours.

Application: Windows | OS X | Processing Source