C code from the article
"A Minimal Ray Tracer"
by Paul S. Heckbert, ph@cs.cmu.edu
in "Graphics Gems IV", Academic Press, 1994

files:
    README		- this file
    minray.c		- "readable" minimal ray tracer
    minray.card.c	- minimal ray tracer for business card
    ray.h		- header file for test scene
    minray.ps		- John Hartman's postscript ray tracer
			    (on UNIX, run "gs" or "lpr" on it)

    minray.post		- messages posted to comp.graphics announcing contest
			    and results.  Contains three shell archives of
			    all the contest entries.

Note that there may be some tricks used in this code that are not
portable to your machine!
