The n-queens problem began as a much simpler puzzle, and was first posed in an 1848 issue of the German chess newspaper Schachzeitung by the chess composer Max Bezzel.

Instead of placing eight queens on a standard 8-by-8 chessboard (where there are 92 different configurations that work), the problem asks how many ways there are to place n queens on an n-by-n board.

The toroidal problem seems simpler because of its symmetry. Unlike on the classic board, all the diagonals are the same length, and every queen can attack the same number of spaces: 27.