Offtopic: mechanical calculators (cardboard and wood!)

A few days ago I happened to stumble with this fun article of a mechanical 4-bit calculator made in cardboard. Even if it’s quite unreliable, is interesting to see the methodical approach and all the creativity to make this work with only cardboard and marbles.

In the comments of the article there is a Youtube video of a calculator that implements 6-bit addition made in wood. It is very reliable, and it takes a completely different approach.

Wat

Fun moment: Wat