Holy smokes, that’s amazing. Never seen the like before. I figured for sure it was a hydrologic process, something to do with aquifer recharge. The truth is even stranger.
That was my first thought. Some sort of artifact of an eddy current. I just couldn’t come up with any combinations of currents that would get anywere close to that pattern. Then I read the story.
Only one thing to do at that point. Start a thread!