LENSES.GIF               size: 1024 x 768            October 1, 1994

     This is a ray-traced study of refraction. A fractal image is mapped to
a plane surface and a sphere. A lower lens refracts part of the plane, and
an upper lens refracts most of the plane and sphere, including the 
refraction of the lower lens.
     The image is a simple Mandelbrot set, but it also is a tribute to
Fausto Barbuto of Rio de Janeiro, who has been an inspirational influence
on the FRAC-L LISTSERV list. The set itself is filled with a "Perturbated
Gingerbread Man" image. The first project I got involved with after joining
the list was to adapt a C language version of Fausto's PGM program.
     When by coincidence I was able to meet Fausto this summer, we looked
at some unusual coloring schemes for the escaping points of the M-set.
This image utilizes a variant of a scheme of level set decomposition that
Fausto came up with afterwards.
     
     Mike Sargent      University of Vermont      <msargent@moose.uvm.edu>