FourKnot is a five-piece assembly puzzle. The object is to put the pieces together, such that they form a continuous loop. The solution is a knot shape that has four crossings, according to knot theory. This makes it the second simplest knot. The knot pieces loop like rope with five stands. The piece are held together by ten 5x5x5-mm magnets. The puzzle is quite confusing. Other than making the knot, one can fold various rope shapes.
Designed by Oskar van Deventer and printed on his Dutchy 3-D printer using a material called "3D-printed wood." It is actually transparent PLA with a lot of very fine mahogany wood grain mixed into it. This makes the puzzles smell a little like scorched wood. Oskar chose this material because of its rough rope-like looks. The puzzle takes 7 hours and 13 minutes to print, 23.7 meters of filament, and some time to clean it up, to glue in the magnets and to assemble.
Oskar van Deventer has created many different puzzles including his brand of Oskar Puzzles which are mechanical puzzles and objects that can only exist thanks to 3D printing technology. Since 1978, he has been creating hundreds of mechanical puzzles, making him one of the world's most prolific designers. Several of his innovative designs are commercially available.