Quite probably the best known puzzle in the world - cube consisting of 3x3x3 matrix of colored cubes, that can be rotated per layer.
Choose the front face - the one facing you. Then the letters denote:
- rotate the front face of the cube clock-wise
- rotate the rear (back) face of the cube counter-clockwise (clockwise if you would make it front)
- rotate the right face of the cube upward (clockwise if you would make it front front)
- rotate the left face of the cube downward (i.e. also clockwise)
- rotate the top (upper) face of the cube to the left (i.e. clockwise)
- rotate the bottom (down) face of the cube to the right (i.e. clockwise)
- rotate the middle slice of the cube upward (clockwise, as R turn)
- rotate the middle slice to the right (clockwise, as D turn)
- rotate the unseen middle slice clockwise (the slice between front and rear faces)
- rotate the whole cube upward (clockwise, as R turn)
- rotate the whole cube clockwise (as F turn)
- rotate the whole cube to the right (as D turn)
The primed letter means change of direction to counterclockwise: F’, B’, R’, L’, U’, D’, M’R, M’D, M’F, G’R, G’F, G’D.