Gear Cube involve either half turns or a full rotation. It has six stationary centers, each with a different color, that always stay opposite from another specific center. White is always opposite of yellow. Blue is always opposite of green. Red is always opposite of purple. Each center determines what color that side will be. The centers are exactly based on the original Rubik's Cube. They are connected by a three dimensional cross with screws and springs allowing for less tension. Many cube solvers use the same notation when completing a cube, whether they are working on the original Rubik's Cube, the
Impossible cube ambiguity present in a Necker cube illustration, in which a cube is drawn with its edges as line segments, and can be interpreted as being in either of two different three-dimensional orientations. An impossible cube is usually rendered as a Necker cube in which the line segments representing the edges have been replaced by what are apparently solid beams. In Escher's print, the top four joints of the cube, and the upper of the two crossings between its beams, match one of the two interpretations of the Necker cube, while the bottom four joints and the bottom crossing match the