Constantin Metal Bike Puzzle Brainteaser from Recent Toys - Advanced Problem Solving Fun for Ages 14+ Constantin Metal Bike Puzzle - Pedal into the World of Mechanical Marvels! Its time to ride - but can you figure out how to remove the padlock first? The most advanced puzzle in the Constantin Metal Puzzle Series. Embark on a journey of mechanical fascination with the Constantin Metal Bike Puzzle, a meticulously designed blend of artistry and enigma. Crafted with precision and ingenuity, this puzzle promises to engage your intellect and add a dash of adventure to your collection. Jean Claude Constantin is one of the more prolific puzzle inventors of the past 30 years. His creations make beautifully unique gifts and his wire puzzles are inspired by everyday objects such as bicycles, telephones and light bulbs.