"If one could find a specific date for birth of personal computing, it would be May 5 1966, when Stephen B Gray founded the Amateur Computer Society and began publishing a quarterly called the _ACS Newsletter_" (BYTE 1978) #retrocomputing https://archive.computerhistory.org/resources/access/text/2012/03/102654910-05-01-acc.pdf
"The simplest computer for which the schematics are available is the Univac FLODAC, which is actually a fluid-logic demonstrator." #retrocomputing
@th at around 5:15 into the video at the bottom of the link you can see the MONIAC[1] in action
https://www.bbc.co.uk/blogs/adamcurtis/entries/9bf2f6f3-4d3d-3756-9841-d702cc884c46
1: https://en.wikipedia.org/wiki/MONIAC