Burr Puzzle A block

thingiverse

The Diabolical Structure is a beginner's puzzle that requires only six pieces to form a Burr shape. Typically, it takes three identical pieces and two distinct ones to complete the design. In this specific puzzle, one of the last pieces is known as the key, labeled A, which serves as a lock to hold everything in place when correctly positioned. Despite its reputation, The Diabolical Structure is not an overly challenging puzzle and can be solved with minimal effort.