Minus Cube Cube is 12 times more difficult to solve. However, if one does not confine oneself to these two types of the Minus Cube, there are 48 Minus Cube variants which can be solved. Minus Cube The Minus Cube () is a 3D mechanical variant of the n-puzzle which was manufactured in the Soviet Union. It consists of a bonded transparent plastic box containing seven small cubes, each glued together from two U-shape parts: one white and one coloured. The length of one side of the interior of the box is slightly more than twice the length of the side of
Helicopter Cube thus jutting outwards like spikes rather than lie flat on the face of the cube. More subtle changes may also be introduced, which are described later. There are four variants of the Helicopter Cube: If the puzzle is only scrambled using 180° twists, then it is obviously solvable using only 180° twists. However, if some jumbling moves were made, even if the puzzle was subsequently returned to cube shape, it may not be possible to solve it using only 180° twists. The reason for this is that using only 180° twists, each face center piece can only be permuted within