What is the maximum number of queens that can be placed on a standard 8x8 chessboard such that no one of them is capable of attacking any of the others in a single move?
Obviously, you can't have more than 8, since you would have a row (and column) with more than one queen on it.
According to Wolfram-Alpha, there are
12 unique solutions, plus an additional 80 solutions from rotation/reflection.
One possible solution is:
A list (and images!) of all