RIDDLER – This machine has two levels of vibrating screens with circular holes. Blanks, planchets, and coins are deposited on top of the upper screen. The upper screen has holes that are just a bit larger than the discs. It allows normal-size discs to fall through but excludes significantly oversized discs. The bottom screen has holes that are smaller than a normal disc. Undersized discs and fragments fall through the holes while normal-size discs remain above the screen. The latter are then moved on to the next step of the production process.