This program was missing in the Amiga version of PBMPlus.

ppmpat is just a demonstration for the ppm drawing routines.
Most options create a boring checkboard-like pattern, but -camo|-anticamo,
-poles and -squig patterns are quite interesting (especially -squig, since
they can be tiled).

Try this:
    ppmpat -squig 320 200 > sq.ppm
    pnmtile 640 400 sq.ppm > sqtile.ppm
