When did the windmill originate?

"Windmills often turn, people live long, there is no wind, there is no wind, the wind blows the car and the car turns happy." Windmills are the most popular toys at temple fairs. Holding a windmill in his left hand and a string of Sugar-Coated Berry in his right hand, eating Sugar-Coated Berry and playing with windmills are sweet memories of countless friends when they were young.

At present, there is no way to verify the age of the windmill, but there is a beautiful small windmill on the head of the vendor in Li Hao's "The Salesman Map of the Song Dynasty", which shows that at least in the Song Dynasty, windmills have appeared and become popular in rural areas.

The most basic components of windmill are rotating shaft and blades. As long as the blades of the windmill are inclined in the same direction and there are shafts that can rotate freely, various windmills can be manufactured.

The most common kite in Beijing temple fair is a traditional kite that can make sound. The structure of this kite is a little more complicated. It needs blades to drive the rotating shaft to rotate together, and the gear on the shaft moves the small rod to beat the drum continuously.