Hanayama Puzzle: Keyhole

Here is a challenging maze. At first glance, the two pieces have simple concave and convex angles on their flat surfaces. However, when the two pieces intertwine, they take the shape of a 3D maze. You must twist and turn them around. If you rush without thinking, you will come to a dead end. Be careful as you may end up going around in circles.The theme is "groove." Designed by Vesa Timonen from Finland.

Hanayama cast puzzles are some of the world's finest brain teasers. These high-quality, cast metal puzzles come in six challenging, Mensa-rated levels of difficulty.
These Level 6 puzzles are considered very difficult by most puzzlers. Hanayama puzzles are recommended for ages 12 and up.

Difficulty 4 stars
Ages 12+