Yeah I’ve tried to wrap my head around that too. Like maybe if you have two people holding a taut rope and they walked in the same rotational direction while keeping the rope taut? But yeah seems like you’d definitely need something in the center to pivot around or else it would be really easy to get it wrong.

Like take this recent (imo definitely man made) formation from July 14th where you can clearly see holes in the center of the circles where they put a pole to pivot around (and conveniently along the farmer’s tram lines):

(I didn’t post this one here since it’s a shoddy man made “crap” circle, lol jk it is decently done but not a finished work I would say)