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Block Chain. At first glance, you may not know how this puzzles behaves or what is its purpose but, once you figure out how to move it, you'll see clearly what you're suppose to do. This was one of the entries at the 24th IPP Design Competition, in 2004 and at the time it was simply called QRIN X.

The presentation of the puzzle resembles a bicycle drive chain and the goal of the puzzle is similar to the Elastic Cube (a.k.a. Snake Cube), where you take it apart and then assemble it back to a cube form. All the parts in the puzzle connected, except at both ends. Some segments are connected by a screw, limiting some movements (just like in the Elastic Cube, where you have two or three cubes connected in the same orientation) but, at the same time you can rotate these segments in the screw's perpendicular plane. One thing to take into consideration, which helps to solve it, is that each segment belongs to one face of the cube and one face only, although you may have more than one segment per face.

Once you take the puzzle apart for the first time, you're in for a surprise, because it's actually two puzzles in one. As you'll notice, the inner core of the Block Chain is a three-piece Burr as you can see from the pictures below.

Overall, a very nice puzzle. Original for its looks and for the hidden extra puzzle.

Currently, you can get a Block Chain at Dino Direct.

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