Three identical pieces make a cube via coordinate motion. This puzzle was invented by Bruce Patterson.

Print three copies of the piece. I have included two versions of this piece. patterson_offset100.stl has an offset of 0.1 mm, it should fit loosely, try this first. patterson_offset50.stl has an offset of 0.05 mm and will fit more tightly, it requires a more accurate printer.

After printing, slide the pieces together in pairs to break them in. This should rub off any printer inconsistencies. I printed the tight version and after some break-in the pieces slide together nicely.