Water Based Analog Computer

Other entries in the history of fluid-based computers:

John Conway was involved with a water-based computer, WINNIE, in the 1950s as an undergrad at Cambridge:

http://nautil.us/blog/this-early-computer-was-based-on-a-uri...

Fluidics: https://en.wikipedia.org/wiki/Fluidics

http://www.blikstein.com/paulo/projects/project_water.html

This shows how the gates above look: https://i.imgur.com/70jHICi.gifv