Harmony

No idea how it works, seems to have been written entirely in Javascript. But the effect is amazing: Harmony - procedural drawing tool. I drew the image posted here on the left in a few minutes. Using the touchpad on my laptop. (via Drawn!)

Update: could not help myself and played with it again the next day (image on the right, just using shaded mode). And then found out that if you press Contol you can select a color to draw with. So I guess I need to play with it a bit more...