When I looked up fairy circles, the Wiki entry had a link to something called Mima (pronounced meema I believe) mounds. For me, this was a happy accident. I have driven the road between here and Merced a number of times, and where the foothills peter out into the valley floor, the ground has an interesting texture, almost quilted-looking. The effect is especially noticeable when the sun is at a low angle. I've been wondering how they came to be.
Mima mounds are also a mystery at present. Some researchers have suggested that millennia of gopher action made them, but that hypothesis has problems, and I've seen no really plausible explanations for them.
It was cool to happen upon the answer to a fairly long-term wondering.
They look like the standing waves one can set up in a shaken bucket of sand. However, these guys consider the seismic and the biotransport hypotheses to be flawed.
https://www.sciencedirect.com/science/article/pii/S0169555X16305062