Alternating Cube was suggested by Bram Cohen at the Twisty Puzzles Forum as follows: "Hey Oskar, can you design a 2x2x2 which must alternate clockwise and counterclockwise quarter turns?". Bram suggested to use the core of Alex Black Hole as a basis. To this, Oskar added the concept of the Enabler Cube. One corner, the "enabler", moves through the core in a CW-CCW fashion. The mechanism inside the core pins one of the corners to the core opposite of the "enabler".