3 bar linkage computing by Svoboda. MIT rad labs, ww2. Cams and drums did a lot of work plotting bomb angle, gunnery, rate of descent.
"He shows that with two basic mechanisms, the harmonic transformer and the three-bar linkage, it is possible to perform the fundamental operations of arithmetic, addition, subtraction, multiplication and division, and to generate ballistic functions." - JOHN WOMERSLEY (https://www.nature.com/articles/162085a0.pdf)