The Sudoku of the 17th century
The sudoku of the 17th century: Sangaku
“ Perhaps it's not surprising that sudoku - the number puzzles that everyone seems to be working on these days - first became popular in Japan before spreading across the ocean. The fad is reminiscent of a math craze that swept the islands centuries ago, when ardent enthusiasts went so far as to turn the most beautiful geometrical solutions into finely illustrated wooden tablets, called sangaku, that adorned the walls of local temples and shrines.”
first read on Collision Detection