I was about to create such a website a couple of years ago, but isn't this too much computational expensive to be a free service? It's going to make people wait a lot if the service hits HN or something like that. Or maybe my code was too much unoptimized and it's possible to train the images in a quite faster fashion after all. Anyway would be great to have such a site.

EDIT: Now I checked better your implementation and is very different, and indeed, can be made a lot faster. What I (and others before me) do is to have a fixed set of polygons and move, rotate, change color in order to find the best arrangement. In your case instead you add shapes incrementally in order to lower the error.