The program text itself is a "Magic Eye" image -- look through the program text and it becomes 3D!
http://www0.us.ioccc.org/2001/herrmann2.c
And what does the program do? It generates "Magic Eye" images, including itself!
See http://www0.us.ioccc.org/2001/herrmann2.hint for an explanation of the program.
For more information about Single Image Random Dot Stereogram (SIRDS) see
http://www.tnt.uni-hannover.de/soft/compgraph/sird/sirdsfaq.txt
