Houdini Puzzle Locks _ 2 Unique Trick Locks _ Bonus Twisted Nails Puzzle Set of 2 different Houdini-style puzzle padlocks. Solid steel locks with 2 keys each. Takes more than a key to open. The puzzle if figuring how? Includes: Houdini Dead Lock Puzzle and Houdini Under Lock and Key Padlock Puzzle. Bonus Twisted Nails Puzzle. Can you separate and rejoin the two twisted nails ? Puzzle Padlocks are a moderate challenge. (Probably 2 on a scale of 1 to 6). Your experience could differ.