Math Teacher Teaching Aids School Science and Technology Museum Science Gift Assemble Wood Burr Puzzle Burr Puzzle Three Yuan Small Pyramid

The ancient traditional fixed combiner of civil architecture is widely spread among Chinese people, there are names such as "Don't be bored", "Liu Zi Lianfang", "Monet he", "difficult Wood", "Kong Ming lock", "Luban Lock", etc., without nails and ropes, supported by the connection of its own structure, just like a piece of paper can stand up after being folded in half.