Hanayama U & U Puzzle
Two U-shaped bolts and four nuts - this looks like a combination of spare parts but looks are deceiving. This puzzle comes with a deviously hidden trick. The key to unlocking these parts is to look carefully at each part first.
As quoted by the Puzzle Wanderer when solving the puzzle: "U&U danced an elegant dance of moves in front of my very own enthusiastic eyes!"
The theme is complexity. It was designed by Kyoo Wong.