Pinwheel 1.0

Pinwheel is a mechanical cilinder type calculator. This type of calculators were designed about 1850 and were in use until 1970. Electronic calculators already existed at this time, but they were very expensive.

The principle consists of a cilinder with 1..9 extendable pins per digit position.
During a revolution of the cilinder, an extended pin advances a gearwheel,
incrementing or decrementing the digit, depending on the direction of the rotation.