How does water flow up in AFK pools?

In a very basic AFK pool, water flows in a circle, but it appears to flow up, as shown below:

Why does this happen? Is it a visual glitch, or something else?

1 Answer

This is no glitch. What is happening, is that since the water detects the water block above it, it rises up to try and smooth out the graphics. Here's an example:

That's literally all it is, the graphics trying to look better by being smooth.

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