A peaceful rook moves on a chessboard like a rook, except that when he comes to another piece, he stops just in front of it (instead of capturing it). Moreover, such rooks always move as far as they can along any row and column (until blocked; if they do not run into a blocker, they fall off the end of the board).
Starting from the configuration of 7 rooks on a 7x7 board shown, find a sequence of moves that moves the rook in the upper left to the empty square in the center.
© Copyright 2001 Stan Wagon. Reproduced with
Source: The puzzle was developed by Hiroshi Yamamoto in 1998 and is marketed by Binary Arts under the name "Lunar Lockout". See: