If anyone is having difficulty with English electronics jargon (or even some basic electronic concepts), I found that this page is quite helpful.
Bookmarked, Thanks for sharing
Very interesting, it would be cool to see to see some basic logic gates made out of hydraulic "transistors".
Of course, the simplest is the OR.
A ===\====
]===== out
B ===\====
\ is a passive valve (working as a diode)
if A or B is under pressure OUT is under pressure
for an AND port you need active valves that open under pressure of a 3rd tube. (with a spring inside to close it again if pressure is released.
put 2 of those in series and
P ===[A]====[B]==== out
P = constant pressure (~ +5V)
if valve A opens uner pressure and valve B opens under pressure => out will have pressure
An invertor is made with a valve that closes under pressure
P ===[in]==== out
homework, design the XOR 