Some may enjoy this, using PovRay CSG to illustrate answers
to geometric problems.
http://astronomy.swin.edu.au/~pbourke/geometry/toruscut/
Before you look ask yourself,
How many ways can a torus be cut (with a single plane)
so that the resulting cross sections are perfect circles?
--
Paul Bourke
pdb_NOSPAMswin.edu.au
