The Constrained Cube is a variation on the regular Rubik's Cube, where the rotation of faces can be limited to 90 or 180 degrees to make solving the puzzle more difficult. This is achieved by having a cogwheel attached to the core, around which the centre piece rotates. The Constrained Cube uses a combination of custom pieces and regular Rubik's Cube pieces.
There are many possible variations of the Constrained Cube. It is possible to choose a different rotational freedom for every face by combining the modular pieces. There are parts that allow full rotation, parts that constrain the face to 180 and 90 degrees and parts that do not allow the selected face to move at all. There are also parts that will constrain a face to 270 degrees, but since going 270 degrees one way is the same as going 90 degrees the other way, they do not change the solving experience (but they could be nice as a joke for speedcubers!). These are the various blocking pieces:
I am still looking for a way to manufacture this puzzle. I may produce a limited quantity by 3D printing, but I think this puzzle has commercial potential. Please contact me if you are interested in producing this puzzle with me.BACK