This puzzle made by Lagoon Games is a good example of an impossible dovetail joint. This is a type of impossible object, so called because there appears to be no way to separate a dovetail joint which consists of a dovetail on all four sides. To make the puzzle harder, a magnetic lock is inside and it has to be released before the two parts of the puzzle can be separated. Complete with instructions. Because the idea of this puzzle is to take it apart, people interested in mechanical puzzles also classify this as a Take Apart Puzzle.