Hi,
My latest MOC is an old windmill, a smock mill, with a typical octagonal plan.
The fantail (the small windmill mounted at right angles to the sails) at the rear of the windmill turns the cap automatically to bring it into the wind.
... the backside of the mill with a small well.
The sails and the cap is fully rotatable.
Here you can see the "round" octagonal design.
... the front side of the mill.
Thanks for watching!
ThomaS