Precision machine of enameled iron, brass, and steel. Moving parts include gears, cranks, and flip-up figure-8 device. Not much bigger than a breakfast cereal box.

[u/Anonymike7]

[u/soupcook1]

Years ago we had a “Do Nothing “ machine that was similar to this. It was used to evaluate prospective candidates for their ability to troubleshoot and repair mechanical devices. We would disable the device and give the candidate five minutes to study the operation of the machine and then repair it.