Following are two screen-savers.
One implements Conway’s game of life, and the other does Recursive Sphere Ray-tracing.
The ray-tracer can be run in ‘application mode’ as well, but it’s pretty nice as a screen-saver.
The spheres are lighted using Phong illumination, including Specular-Highlights, recursion level is limited to your stack, or in other words none
Life Screen-Saver (Source + Win32 Binary) : life_saver.zip Sphere Tracer (Source + Win32 Binary) : mini_tracer.zip