This is the kind of thing that I love about antique equipment. Someone came up with this concept long before the age of electronics, probably using a slide rule.
Totally functional by design with an inherent beauty of motion.
Cycloidal Drive or Cycloidal Speed Reducer. A mechanism to reduce the speed of an input shaft by a certain ratio. They are capable of relatively high ratios in compact sizes. The input shaft drives an eccentric bearing that on turn drives the cycloidal disk in an eccentric, cycloidal motion.