See the given image carefully. What you have to do is move the blue checkers in the position of the black checkers and vice versa. You are only allowed to move the checker to an adjacent empty space. Do it in the least possible moves.

Can you move 3 matchsticks to flip the chair back to the original position?

See the following chess case and it’s White's turn to move. If both White and Black play optimally, what is the minimum number of moves for White to checkmate the Black king?