Nut Stack is a packing problem. The objective is to fit the bolt and the four nuts into the pentagonal box. The way to do this is to fit the nuts around the bolt and put these together into the box. Each of the nuts is pentagonal with an elongated side. When one turns the nuts around the bolt, all nuts stacked together form a pattern. Only one of all 12x16=192 possible permutations and combinations matches the pattern of the box.
In order to make the puzzle more accessible, each of the nuts has two little black markers. When any two nuts are bolted together, their markers line up. This makes it easier to try and analyze the puzzle.
This interesting puzzle has been 3D printed by designer Oskar van Deventer. The box, bolt and four nuts took 9 hours to 3D print on a Dutchy 3D printer. 35 meter of 1.75-mm PLA filament was used to print it: mahogany wood for the box, birch wood for the nuts, and matte black PLA for the bolt and the markers on the nuts. The puzzle weights 98 gram.
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.