A set of notched wooden pegs create a 3x4x6 Burr puzzle, the origin of which is quite old. Burr puzzles can have hundreds of internal cuts and still "notch" together to form the X-Y-Z axis shape that you see in the picture. This Burr requires insertion, twisting, sliding of some of the pieces. Very difficult to solve!

Difficulty level: 4 (out of 6)