Hi Twisty Puzzles fans, Tracker Ball 3D is based on an idea by Bram Cohen. A large central sphere gear with icosahedral symmetry meshes with four smaller sphere gears that have octahedral symmetry. The puzzle as a whole has tetrahedral symmetry. The object of the puzzle is to scramble it by randomly turning the central gear, and then solve it by getting all colors aligned again. Watch the YouTube video. Buy the puzzle at my Shapeways Shop. Read more at the Twisty Puzzles Forum. Check out the photos below. Enjoy! Oskar