I went to one in Germany where it's a circle with several urinals pointing inward. I think the center fills with pee and then...profit??
Historically, they used urine to tan animal skins, so families used to all pee in a pot. Once a day it was taken and sold to the tannery.
If you had to do this to survive, you were piss poor.
But worse than that were the really poor folks who couldnt even afford to buy a pot. They didnt have a pot to piss in and were considered the lowest of the low.