Built with Processing
Plankton

Growing by simple construction rules, these organisms develop very complex structures. If your computer has sufficient processing power you can even watch them move and change shape in realtime. Many of those forms remind me of Ernst Haeckel's drawings from Art Forms in Nature. (Well, some look more like the old Eurovision logo).

Press any key to grow a new organism (if the applet doesn't react you have to click it once to set the focus).