The 4x4 cube is a twisty puzzle that has the shape of a cube, with 3 axes. Each axis has 3 cuts along it, giving rise to 4 layers in total. It has a total of 24 center pieces, 24 edge pieces and 8 corner pieces.
The 4x4 cube (called the “Rubik’s Revenge”) was invented by Peter Sebesteny and released in 1981. Like most cubes of even order (2x2, 4x4, 6x6, etc.), it has no fixed centers, and so construction and design were a major challenge.
Since its first market release, there have been massive developments in mechanism and smoothness, especially by companies such as ShengShou (originally) and followed by MoYu, QiYi and other cube giants.
Today, with the inclusion of magnets, 4x4 cubes almost turn like 3x3 cubes, which is an indication of how far their production has come since their conception.