I generated these images using OpenGL under Windows some time in 2000, perhaps early 2001. They were inspired by similar (but better) work by Laurens Lapré. Please feel free to download them and use them as wallpaper or whatever you want.

I used arrays of cubes and a bunch of random numbers. With the first image the numbers dictate size and colour, with the second and third it's just size (in the third image the camera is positioned within the larger cube). With the fourth image I used a random number to dictate if a sphere should be placed instead of a cube and then decided that sphere's size randomly.