Diamond 16 Puzzle Rearrange rows, columns, and quadrants in a 4x4 array of 2-color squares to solve the puzzle and to make a variety of symmetric designs.
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.
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).