Combination puzzle 27 pieces

Six-piece interlocking puzzles are probably the most familiar puzzles to all puzzle lovers today. This box contains 27 pieces to create dozens of six-piece interlocking puzzles.

The German mathematician De Boer conducted extensive research on all types of crossword puzzles. Over the course of about 10 years, he calculated and found all possible combinations of types of pieces (2906) from which an infinite number of puzzles can be assembled.

Each puzzle includes 5 different rods in addition to the locking rod - the only complete rod (rod number zero). There are 69 different ways to assemble puzzles from the 27 pieces.

A must-have item for collectors.