No text, but a visual code

[denty]

I agree with Antonio that although I can see the upper somewhat straight sections and the lower bulbous sections in each diagram, I don't really see any other resemblance. In the balneis one there is no water in the straight upper part, the other one, boats are in the water, the people are on the shore, plus there are more water connections there.
I don't think it is a water slide, it just gets deeper from top to bottom.