Display hack

A display hack is a computer program with similar purpose to a kaleidoscope: to make pretty pictures (symmetrical or otherwise). Famous display hacks include munching squares and smoking clover. Some display hacks can be also implemented by creating text files which contain numerous escape sequences for a text terminal to interpret. A famous example on the VT100 terminal displayed a Christmas tree, with twinkling lights and a toy train circling its base. The XScreenSaver software contains a large collection of X Window System and OpenGL display hacks.