Starfish for Mac

From Red Planet Software:

Starfish generates desktop wallpaper patterns. It is a utility, a toy, an amusement, a decoration; a lightweight work of digital art. Starfish mixes random numbers and mathematical formulas to create unique, eye-catching abstract images. You choose a color palette (or let Starfish create its own) and a tiling size (or use the full monitor size) and the software does the rest. Starfish will automatically create new desktops on a schedule you select, or you can simply generate new images whenever you get tired of the old ones.