About

The Turnstile puzzle consists of two overlapping circular disks. Each disk has 12 pieces, 6 are triangular ('corners'), 6 rectangular ('edges') alternating along the rim of the disk around a hexagonal centre. The pieces have curved sides. The disks have three pieces in common, two corners and one edge, so there are altogether 10 corners and 11 edges. Each disk can be rotated. A rotation should be a multiple of 60 degrees since only then can the other disk move again. There are 5 bright colours used for the corners, a pair of each colour. There is one edge of each of those colours, and the remaining 6 edges are grey. The aim is to put together all pieces of the each colour. The only way to do this is by forming coloured 'lozenges' of two adjacent corners and the edge between them. These lozenges are separated from each other by the grey edges. The rim of the puzzle has small coloured markings, so that the colours of the lozenges should be such that they match the markings. Turnstile was manufactured by Binary Arts (now called ThinkFun). There is also a version called TwinSpin that was made in the far East. Turnstile was licensed however from Douglas A. Engel who originally invented and produced it. He patented it on 15 November 1983, US4,415,158. He first called it Engel's Enigma, but later marketed it as The Puzzler with three different designs of varying difficulty: Puzzler variations Novice: The pieces of one disc are blue, the rest red. Challenger: The top half of the discs is green, the bottom half yellow, and the three edge pieces in the middle are black. Avenger: Like Turnstile, but with the colours yellow, red, green, blue and black, and using white edges to separate them. There are no colour markings on the puzzle rim. Note that the Puzzlers sold in the USA were manufactured there and have a hexagonal white base, whereas those sold in the rest of the world were made in Taiwan and have a black oval base. These puzzles were invented by Douglas A. Engel, who also invented various other puzzles such as: Battle Gear Farmland Gear puzzles Palette 21 Palette 7 Palette Mix 4 Slide Rule Duel (Binary Bisection 5) Slide Rule Duel Pentaplenty and Heptalive If your browser supports it, you can click on the link below to play with a Javascript version of the Turnstile puzzle or any Puzzler variation.