Our county park day camp had one in the 60s. (Might still be there.) Real basic round concrete area with a lone straight up pipe with some kind of shower head on it that sprayed out in every direction.
I remember it because my brother (a year younger and about 10) stepped on some broken glass and one of the counselors carried him out to the grass area to pull out the glass. No permanent harm done but not a fun day for him.
Your pic is as close to the vibe as anything I’ve seen. But the spray on top was not as complicated, and the entire circular area was depressed.
It’s hard to tell from that picture but it’s definitely a slight bowl shape
They’re all going to have some sort of gentle slope so the water is running towards a drain, not just sitting out there on a truly flat surface to eventually evaporate.
Some of those slopes are real gentle and not-obvious when the water is not running. If the water is running, it becomes real easy to see the slope as reflected in the behavior of the water.
Just for clarity: What I recall is a circular vertical wall of 1’ or so in height, down to a nearly flat (tho enough slope to drain) floor. Essentially the bottom of a cylinder. Cut off the bottom of an oats container.
If you saw one, you would not say anything like “definitely a slight bowl shape.”
Sorry I lack the terms to describe the shape well.