If anyone had been around, they would have remarked on the obscure chances that the sea, gently lapping on the beach, could deposit 100 stones in a perfect circle.
They stood out as they were from a darker type of rock than the rest on the beach. The precise type this author hasn’t the inclination to properly research. A basalt, maybe?
The circle really was surprisingly circular, though the laws of probability decreed that it shouldn’t be any more surprising than any other particular dispersal.
Then, because somebody forgot to put 50p in the meter, the universe suddenly switched off.