Calvins Puzzle TomZ Constrained Cube 180

Calvins Puzzle TomZ Constrained Cube 180

At first glance it looks like an ordinary 3x3 cube, but after a few moves a face simply stops turning. On the TomZ Constrained Cube 180, each of the six faces can turn at most 180 degrees in one direction. After that, you have to turn it back the same way, so no face can ever make a full rotation. The puzzle was designed by Tom van der Zanden (TomZ), whose designs include the Curvy Copter, and it is manufactured by Calvin's Puzzle. We offer the stickerless bright version, made of coloured plastic with no stickers.

How the restriction works

Next to the core of each face there is a small gear that the center rotates around. This gear sets the range of motion. The centers are larger than on a regular cube, so the restriction is easy to see. In practice, two quarter turns of a face in one direction will go through, but a third will not. To turn the face further, you first have to turn it back.

How to solve it

3x3 algorithms still work, as long as no face goes beyond its range along the way. Short sequences like R U R' U' are safe, because every face returns to its starting point. With longer algorithms, and even during the scramble itself, you need to keep track of how much movement each face has left. Sometimes you will also have to change the order of moves or turn a face the other way. Solving it takes more planning than a regular 3x3, and muscle memory alone is not enough.

This is a brain teaser, not a speed cube. It has no magnets, and the turning is noticeably less smooth than on modern cubes. One buyer reported catching and lockups on two faces that did not improve even after lubing.

The 180 version vs. other Constrained Cube versions

The series comes in several variants:

• 90: each face turns only a quarter turn and back.
• 180: this cube.
• 270: the designer admits it changes little in the solve itself, because 270 degrees in one direction has the same effect as 90 in the other.
• Ultimate: the faces have different restrictions, and one is completely locked.

According to people who own several versions, the 90 is the hardest. The 180 and Ultimate versions are clearly harder than a regular 3x3, but not so hard that they become discouraging. Do not confuse this cube with the 180 & 3x3 Hybrid version, in which only two faces are restricted.

Who is it for?

For anyone who can comfortably solve a 3x3, even with the layer-by-layer method, and wants a puzzle that makes you think through every move. It is also a great addition to a collection of 3x3 mods and TomZ designs. It is not suitable as a first cube, because without knowing how to solve a regular 3x3, it will be hard to solve.

Specifications

• Type: 3x3 cube with restricted face turning (constrained)
• Designer: Tom van der Zanden (TomZ)
• Manufacturer: Calvin's Puzzle
• Restriction: each face within a 180-degree range
• Magnets: none
• Material: ABS plastic
• Colour: stickerless bright