I think of this as the snail spiral. It’s an aesthetically modeled drain in the H4WP*.
I especially like it as a brain-exercise. I step along briskly on the grey stones, voop, up one side and back the other, a couple of times. Stepping on an irregular surface is supposed to be good for your brain. I’m trying to counteract the less…um…toughening…choices I make….
* H4WP=Historic Fourth Ward Park.