This works only with latest git of Minetest (ass of 16.10.13).
With older versions, you'll only see a one node large rotor.

Crafting: MATERIAL     -nothing-  MATERIAL   
                         stick               
          MATERIAL     -nothing-  MATERIAL   

With MATERIAL beeing

         steel ingot for 4-blade windmill
	 homedecor plastic sheet for 3-blade turbine
         white wool for historic windmill sails
         wood for historic windmill without sails (rotates very slowly)
         stick for us-style farm windmill

Clockwise- and counterclockwise rotating rotors can be crafted into each other.


The axis is mostly a decorative node to which you can attach your mill rotors.
   
Axis:     steel_ingot    stick    steel_ingot


Liscences: for code (written by Sokomine): WTFPL (it's really only a demonstration)
           for textures (created by VanessaE): WTFPL