Riddle: 8 Queens On A Chessboard
In chess, queens can move horizontally, vertically, or diagonally, as far as they like, as shown in the picture. We say that a queen can "attack" another piece if it can move into the other piece on the next move. How can you place 8 queens on a chessboard such that none of the queens can attack each other?
This can be solved by trial and error. Put a queen in the top-left corner of the board, and then start moving to the right, one column at a time, placing down queens in feasible spaces, and backtrack if you run into a dead-end.