Pruned: Crypto-water computers – wow, I would never have believed this….

Built in 1936, this machine was “the world’s first computer for solving [partial] differential equations,” which “for half a century has been the only means of calculations of a wide range of problems in mathematical physics.” Absolutely its most amazing aspect is that solving such complex equations meant playing around with a series of interconnected, water-filled glass tubes. You “calculated” with plumbing.