Russian scientist built a computer that ran on water in 1936. Back then, computers were a little different of course. They ran on levers and gears that automated counting in some way or another.
Vladimir Lukyanov computer was the first in the world that could solve partial differential equations. In case you don’t know what those are, it is important to know that they are a pain to solve by hand.
To solve the issue of differential equations, Lukyanov fiddled around with a series of interconnected, water-filled glass tubes. The levels in certain water-filled tubes gave the answers, while adjusting taps and plugs changed variables.
The computer device was actually used to solve problems related to cracks in the concrete. It inspired other devices and applications to be invented and created.
The same technology was then used in geology, thermal physics, metallurgy and rocket engineering. It was a pretty inventive instrument.