A variation on the avoiders algorithm to allow snatching colours from images and circular walls. Here the avoiders are contained within a circle, and the colours are taken from various images of nebula (specifically the horsehead nebula), resulting in tasty planetoids.
See a lo-res online version here, or download the sketch along with the source code here. The sketch is supposed to run a google image search to get the images instead of picking them from a pre-downloaded pool, but I couldn’t be fucked to do the applet signing thing for the online version. If you get the source you can experiment with different search terms. Spacey searches seem to work well (sticking with the planets thing), but then so does “meat”, strangely.