Set up a chess board with all the pieces in their correct starting positions. Now remove all the Pawns. There are now four unthreatened squares on the board.
How many, and which pieces can you remove from the board so that the position and number of unthreatened squares remains unchanged?
(In reply to
re: Solution by Patrick Silver)
Sorry Let me clear that up. Both knights on king side and one rook from the left and one rook from the right. Doesn't matter which side