This cube is a Sudoku consisting of up to three levels of '2x2 Sudokus' with base colors, circle colors and symbols on all faces. Therefore the cube name means (4x4x4) cubies x 4 base colors x 4 circle colors x 4 symbols.
In its initial state the cube faces are divided into grids of four colored 2x2 boxes. The four different circle colors are arranged as 2x2 Sudokus on two faces, The four different symbols are arranged as 2x2 Sudokus on all six faces. They appear on every row and column exactly once and they also appear exactly once in each 2x2 box.
The cube can be solved in several 2x2 Sudoku stages with several valid solutions.