A DOS-based graphics demo (in VGA 320 by 200 mode) that uses relatively simple dynamics for simulating the behavior of a "sand picture" (consisting of different types of sand and some water, kept between two pieces of glass), generating a continously moving display. This would be a good thing to turn into a screensaver, but I never got around...
While a real sand picture has to be turned around whenever the sand settles down, this simulation simply reverses the force of gravity to change roles between "grains" and "bubbles". This can be forced at any time by hitting the Space bar.
C source code is included.
Update (2010):There is now an iPhone app using the same algorithms, developed by Thomas Hahn, and available through the App Store. A blog about the development of the app can be found here.
Please note that the entire documentation is in German language only.
This is largely of historical interest for people researching "Undocumented DOS" or for trying to get old DOS boxes to run with weird combinations of TSRs.
Source code is included.