Hi Shapeways fans, 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". Watch the YouTube video. Buy the puzzle at my Shapeways Shop. Read more at the Twisty Puzzles Forum. Check out the photos below. Photos of the mechanism here. Enjoy! Oskar