I created a little processing sketch that draws a filled curve at some random vertices, and then mirrors it and draws it a second time. I like how simple evolving shapes that are drawn twice mirrored along an vertical axis immediately look very organic. So watch the shapes evolve slowly and have fun finding flowers, faces, insects, ...
click here to start the sketch or download the sourcecode.
floating rectangles in processing
corral structures from particle collisions
raindrops processing sketch