Classes of mechanical puzzles disentanglement puzzles : Here some or all of the pieces have to be separated from the other pieces. lock puzzles rearrangement mechanical puzzles : Here the pieces have to be rearranged in a certain way in order to achieve a certain setup. Sometimes such the puzzles is presented in a solved state, but is easily changed into a difficult setup by a few moves by the player. Rubik\'s Cube Easy Cubes Nintendo Ten Billion Barrel trick-knife puzzles