Holistic Ring was conceived by Bram Cohen. He decided to come up with a design which has a nice holistic finishing move, which makes this puzzle quite hard to solve for a four-band puzzle ring. This is the interlocking metal version, a bit more expensive than the plastic version , but very good looking.Watch the YouTube video Read more at the Shapeways Forum Read more at the Non-Twisty Puzzles Forum See also the version by PuzzleRingMaker This model has a size 12 ring. Please contact Oskar , if you are interested in buying this puzzle ring in a different size.