Create a blank bitmap of a specified size
pbmmake [-white|-black|-gray ] width height
Produces a portable bitmap of the specified width and height. The color defaults to white.
In addition to the usual -white and -black, this program implements -gray. This gives a simple 50% gray pattern with 1's and 0's alternating.
All flags can be abbreviated to their shortest unique prefix.
Copyright (C) 1989 by Jef Poskanzer.