When you sit down to assemble a puzzle, even one with thousands of pieces, you at least have a photo of the completed image to work towards. But thanks to some clever mathematics, this Infinite Galaxy Puzzle can be assembled in any direction, or in any shape, leaving you without much guidance on how to put it together.
Based on a scientific curiosity called a Klein bottle, which is an impossible 3D shape whose insides and outsides are mathematically identical, the intricate pieces that make up this infinite puzzle can be transferred to its opposite side by simply flipping them over.
Usually when you start a puzzle you take a few minutes to flip every piece over so the artwork is visible on all of them. But that would be a waste of time here since both sides of this Infinite Galaxy Puzzle feature an image of the galactic centre as taken by the Hubble observatory. In a way, there's no wrong or right way to assemble the puzzle, which makes it more challenging to most, but downright maddening to puzzle purists.
If it sounds like a challenge you're up to, the 133-piece, laser-cut, birch plywood Infinite Galaxy Puzzle is available from Nervous System for $US100 ($134). It includes an image of our galaxy for reference, but it won't make assembling the puzzle that much easier.
There's also a cheaper version, called the Infinity Puzzle, which instead comes with 51 unfinished birch plywood pieces for $US50 ($67) that you can use to create whatever abstract shapes you want since there's no image to assemble.