Most locks unlock with either a few turns of a dial, or inserting a key. But the Schloss 250 is a lock puzzle that requires 250+ moves in order to open its hasp. The solution is relatively simple once you get it, but quite time consuming. The Generation Lock is even more challenging.
Paul Myers designed this replacement interior door knob which can only be opened by dropping a marble into its top. It’s made from 3D printed PLA, Airsoft and skate bearings. You can pick one up in his Etsy shop, Beta Things. We dig his business card embosser too.