This award-winning puzzle looks likean accident you’d find in the bottom of a hardware drawer. However,this is a highly intentional and brilliant design hiding in plain sight. When you first attempt to separate the two U-shaped bolts, you will notice that the nuts do not screw off. Even after some experimentation, it may seem the parts are stuck together permanently. An elegant dance is required to untie the knot.

U&U was named Puzzle of the Year in 2014. Designed by Kyoo Wong of Hong Kong. Manufactured by Hanayama of Japan.