At the time I had far more elaborate drawing of it, but the swept them away. Tonight, I will attempt to explain the workings of this windmill on the basis of the following cross-section, looking down upon the windmill:

Basically, the ground plate of the windmill has five equal-sized cogwheels, or a similar construction that keeps the four satellite wheels perfectly synced through the center one. Imagine the wind coming in from the bottom of the page, and view the thicker straight lines as the vanes of the windmill, sticking out of the page.

Now the left one is perpendicular with the wind, and will be forced backward. The right one is aligned with the wind, and will virtually not be influenced by the wind as it is rotated clockwise because of the forces working on the other three vanes. The top and bottom vanes are half in the wind, and respectively are forced right and left. thus there are always three vanes that exert a counterclockwise force on the windmill.

The five cogwheels make sure all four vanes make this cycle of movement: perpendicular on the left, aligned on the right, and the slanted variations inbetween. But what if the wind starts coming from another direction? Simple: by having the center cogwheel rotating with the direction of the wind, the direction of the vanes is adjusted to the perpendiculare side is always on the left side of the wind direction.

I wished to build a prototype back then (say 15 years ago), but never could find sufficient working parts at reasonable prices. And besides, I never would have been allowed to mount it on the roof of our rental home, which also wasn’t flat. Thus, the cobwebs got hold of it…..