The Cast U&U is a cast-metal puzzle from Hanayama’s Huzzle Cast series, devised by Hong Kong designer Kyoo Wong. It imitates an ordinary piece of hardware: two U-shaped bolts hooked onto each other, each with its nuts. The aim is to separate the two bolts and then reassemble the whole thing.

• BrandHanayama
• SeriesHuzzle Cast
• DesignerKyoo Wong
• MaterialCast metal
• Pieces6: two U-bolts and four nuts
• DifficultyLevel 4 of 6 (Hanayama scale)

Design

Its charm lies in the contrast between appearance and challenge. It looks like any spare part kept in a toolbox, and gives the impression that you only need to unscrew the nuts to free the bolts. However, the nuts do not come off as you might expect and the bolts do not separate easily, so the assembly seems joined for good. Before you start, it is worth examining each part calmly, because looks are deceptive.

It measures about 5 cm and is made entirely of metal, with a finish that reinforces the illusion of an industrial object.

What level it suits

Hanayama grades it at level 4 on its scale of 1 to 6, already in the demanding half. It is a model much loved by enthusiasts for the surprise it holds, and it is usually recommended for those who have already solved an intermediate-level puzzle and are looking for a different mechanism.