If you’re feeling a bit vindictive and want to play a cruel joke on a roommate, then you should definitely check out this puzzle. This Toilet Roll Puzzle makes it impossible to use the toilet paper until you solve the puzzle. Once the puzzle is solved then you’re free to wipe. Just be sure you know how to solve the puzzle before you place it on the roll or you’ll end up paying for the prank yourself. You can purchase it on LazyBone for $19.71.