On Monday, August 11, 2003, at 10:49 PM, Mark Brownell wrote: > On Monday, August 11, 2003, at 09:27 PM, Dar Scott wrote: > >> Sorry about the gobblygook. > > I liked the gobbledygook. Here are more pictures including some work on a similar problem: http://mintaka.sdsu.edu/GF/explain/optics/rendering.html Dar