The Faces/Sides of the Famous Cube is a more challenging problem/game than the original Rubik's Cube, because player can see only a one side of the cube. The aim of this game is the same -to reach the state where each side of the cube has all facets with the same color. There are several levels of complexity with 3, 4, and 5 slices per side.
) "Faces of the Famous Cube for Pocket PC - Click to enlarge screenshot")