The Golden Ratio is discussed at this site:
http://www.geom.uiuc.edu/~demo5337/s97b/art.htm
The Golden Section in Nature is discussed at this site:
http://www.gi.alaska.edu/ScienceForum/ASF7/716.html
There are many sites that discuss the relationship between
math and art (that is between perspective and projective geometry). You need to
look at sites that are not heavily weighted by mathematical notation. One such
site is:
http://mathforum.org/sum95/math_and/perspective/perspect.html
A super interactive site exploring some of the ideas of nonEuclidean
geometry is found using this link:
http://cs.unm.edu/~joel/NonEuclid/
This site explores Saccheri's quadrilateral:
http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Non-Euclidean_geometry.html
Links