This is the Pascal source for the generator used to build the maps tested in

C. Morgenstern and H. Shapiro. 1991.
Heuristics for Rapidly Four-Coloring Large Planar Graphs.
Algorithmica, 6, 869-891.

Generates maps of up to 128K using two possible methods (there are 13
possible ways to generate maps with the triangulation routines, but only
two are invoked by the mainline).  

Compiled with Oregon Pascal-2 and run on a Sun3 with 16 Megs.

Stdin should be three lines containing, in order
  (1) The size of the initial circuit
  (2) A random number stream seed
  (3) A method number (1 or 2):
         (1) reduction method
         (2) expansion method

The generated map is written in DIMACS challenge format to stdout.