This cube does not come apart. The large cube is composed of 6 sides or faces. In the center of the large cube is a mechanism to which the center small cube of each of the 6 faces is attached. Each face is composed of 9 smaller cube-like pieces, with hidden inner tabs on the edge and corner cubes. The tabs ride along a curved inner track formed by the backs of other cubes in each plane.
Pressure exerted by each holds neighboring cubes in place.
An entire face can be rotated because of the center mechanism. It seems all of the small cubes can move, but only the cubes on the corners and edges actually move. A number of variations of the original cube have appeared on the market over the years, such as mini-cubes as part of a key chain, rounded cubes in the shape of a column, and cubes with pictured sides. There have been regional and international competitions in which the colors of the cube have been re-arranged, and contestants race with the clock to restore a single color to each face.