These three metal puzzles are good examples of impossible dovetail joints. 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. The amazing thing about these puzzles is that, although they are outwardly identical, internally the geometries are completely different. They require different solutions to open them. The second illustration which appears when you click View Details will reveal the solutions, so don’t click before you’ve tried to think of potential solutions. To make each puzzle harder, a magnetic lock is inside and it has to be released before the two parts of the puzzle can be separated. Because the idea of these puzzles is to take them apart, people interested in mechanical puzzles also classify these as Take Apart Puzzles. Wil Strijbos is a clever puzzle designer and manfacturer from The Netherlands.