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Since all of these additions were implemented as extensions to PostScript, it was possible to write simple PostScript code that would result in a running, onscreen, interactive program.

Two popular demonstration programs were an onscreen clock, which required about two pages of code, and a program which drew a pair of eyes that followed the cursor as it moved around the screen.

The eyeball program was shown at SIGGRAPH in 1988, and was the inspiration for the later well-known X application xeyes.