A Mathematician's Aesthetics http://m759.freeservers.com/PHaesthetics.html
In his classic A Mathematician's Apology, G. H. Hardy likened mathematics to poetry and painting. This site elaborates on Hardy's remark with quotations from Stevens, Klee, Fry, and Focillon. Links to related sites are given.
The Diamond 16 Puzzle http://m759.freeservers.com/puzzle.html
New version of the classic puzzle using row/column/quadrant permutations to display symmetries of graphic designs. Has link to a site on the underlying mathematics (Diamond Theory).