In chess a knight may move 2 up/down and one sideways, or 2 sideways followed by one up/down. See the following illustration:
How many knights can you put on a normal 8×8 chessboard so that no knight may take another knight? And can you show that that is the maximum?
This problem was posted at the Dutch mathematics olympiad 1996.
You can check your solution here
justpuzzles 