Windmills - Rotation

"Windmills always turn counter-clockwise."

A windmill is a machine that is powered by the energy of the wind. It is designed to convert the energy of the wind into more useful forms using rotating blades or sails. The term also refers to the structure it is commonly built on. In much of Europe, windmills served originally to grind grain, though later applications included pumping water and, more recently, generation of electricity.

The first practical windmills were the vertical axle windmills invented in eastern Persia, as recorded by the Persian geographer Estakhri in the 9th century.[1][2] The authenticity of an earlier anecdote of a windmill involving the second caliph Umar (AD 634–644) is questioned on the grounds of being a 10th-century amendment.[3] Made of six to twelve sails covered in reed matting or cloth material, these windmills were used to grind corn or draw up water, and quite different from the later European versions.