The Rubik's Cube was invented in 1974 by Hungarian sculptor and professor of architecture Ernő Rubik. It is a puzzle game where one must turn the cube's faces to align colored tiles.
The following list of notations was developed by David Singmaster, who was a professor of mathematics at London South Bank University. This notation was developed to easily describe a method to solving the Rubik's Cube. That is to say given a scrambled Rubik's Cube, turn any number of sides until each face of the cube has 9 of the same colored tiles. Utilizing this notation allows algorithms to be created regardless of orientation of the cube. The notation is as follows:
When a prime symbol ( ′ ) follows a letter, it denotes a face turn counter-clockwise, while a letter without a prime symbol denotes a clockwise turn. A letter followed by a 2 (occasionally a superscript 2) denotes two turns, or a 180-degree turn. R is right side clockwise, but R′ is right side counter-clockwise. The letters x, y, and z are used to indicate that the entire Cube should be turned about one of its axes, corresponding to R, U, and F turns respectively. When x, y or z are primed, it is an indication that the cube must be rotated in the opposite direction. When they are squared, the cube must be rotated 180 degrees.
Sources Wikipedia