Reminds me a lot of the marble calculator [0], though with far more moving (and fragile) parts. [0] https://lapinozz.github.io/learning/2016/11/19/calculator-w

Reminds me a lot of the marble calculator [0], though with far more moving (and fragile) parts. [0] https://lapinozz.github.io/learning/2016/11/19/calculator-with-caordboard-and-marbles.html https://lapinozz.github.io/learning/2016/11/19/calculator-wi...