Starting with a bunch of random polygons, Dirty Triangles will evolve a picture, like this view of the Taj Mahal. At each step, one of the polygons is randomly modified, or "mutated": this change is kept only if it makes the set of polygons look more like the target image, otherwise the mutation is discarded.

How quickly the picture will evolve in your browser depends to great extent on which browser you're using. See which browsers are fastest