The image above is an example of generated art from
Evolvotron by Tim Day. To quote the author:

Evolvotron is interactive “generative art” soft-
ware to evolve images/textures/patterns
through an iterative process of random muta-
tion and user-selection driven evolution. If
you like lava-lamps, and still think the
Mandelbrot set is cool, this could be the soft-
ware for you.

I find it just right when I’m too tired to think, but too
wired to sleep. I got several of my favorite destop pat-
terns this way. If you want to try it out, you need the QT
libraries from Trolltech, and the Evolvotron source code.

Since this is algorithmic art, you can save the parame-
ter sets to re-generate images of any size.

In the meanwhile, here are a few more images, with
their parameters.