We have already discussed the Breaking Chocolate Bar and Squares and Circles puzzles. There are quite a few more, some of which are very well known. Most of the puzzles may be played in numerous settings. In puzzles where a move consists ostensibly in changing colors, one may turn coins instead. Puzzles are so numerous that just counting them is in itself a good exercise.
Chessboard Consider a chess board with two of the diagonally opposite corners removed.
The size and the shape of the board may vary. In a 4x4 chessboard, all squares are colored white or black. Given an initial coloring of the board, we are allowed to recolor it by changing the color of all squares in any 3x3 or 2x2 subboard. The same question. Plus or Minus Write a series of integers.