Wire puzzle

Wire puzzles consist of two or more entangled pieces of more or less stiff wire. The pieces may or may not be closed loops. The closed pieces might be simple rings or have more complex shapes.

Wire puzzles have a long history. Early examples were made from horse shoes and similar material.

More than 7000 wire puzzles are known. The mathematician Richard Hess has collected them in a book he privately publishes ('Compendium Of Over 7000 Wire Puzzles', first edition March 1991). Many of them are his own inventions.