No, we didn’t go out at night to garden a little and rearrange stones in circles. This was all done by nature. In winter the top layer of the soil freezes and the water in the soil expands (into ice). Due to this expansion the larger stones are pressed outwards, while the smaller stones and the sand are small enough to go between the ice and stay in the middle. After many years of thawing and freezing these nice circles appear on the ground. Really nice to see what the power of nature can do…