It may consist of only three pieces, but at under a millimeter in size each, we imagine this jigsaw puzzle made at the Karlsruhe Institute of Technology (KIT) is a little on the fiddly side. The researchers involved used the latest in LIGA technology, which combines lithography, electroplating and molding, to make objects which are very tall for their thickness.
LIGA (a German acronym based on the three afore-mentioned production processes involved) was developed at KIT in the 1980s. The involved process uses X-ray lithography to create 3D molds using an X-ray sensitive polymer (or photoresist), an electrical conducting substrate, and an X-ray-resisting mask which selectively exposes areas of the photoresist. The process is used to create molds which can be used to make other components more simply.
The new jigsaw puzzle is a demonstration of what KIT is calling LIGA2.X, a development of the LIGA process which does away with the need for the substrate, eliminating the need to remove it to create the final mold. "LIGA2.X does not only reduce costs, but also ensures higher degrees of freedom in the arrangement of structured mold nests in multiple molds," said Jochen Heneka of KIT's Institute of Microstructure Technology.
So, while you're struggling to put this tiny jigsaw puzzle together (boxing gloves not recommended), you can take comfort from the fact that it was a little more straightforward to make than it once would have been.
July 17 Update: Hold fire on the "world's smallest" accolade. Gizmag's Brian Dodson has trawled the Way Back Machine to find this 2004 press release (which is in German) from Laser Zentrum Hannover e.V. announcing a femtosecond laser-cut jigsaw 5 x 5 mm (0.2 x 0.2 in) with 100 pieces, each the size of a speck of dust. So chalk this up as the world's second smallest jigsaw puzzle … probably.