The scaled Dutch windmill outside our hotel was hand crafted in 1996, and you still see similar full size ones all over the country, their huge wooden blades, vented and rotating on a smooth ring bearing. Now there are many modern windmills that look space age, generating electricity as soon as there is the slightest breeze.

This little one decorates a pool beside the freeway hotel and restaurant complex we stayed at.

And it spun with the slightest breeze, even with all the holes in the blades. There is twist and shape like an illusion, a bunch of flat straight pieces of wood creating a virtual smooth form through the air. In fact it would probably be very interesting and rewarding to do CFD on these blades. There must be something about the heavy weather feathering that is the highly empirically evolved thing. The twist of the leading edge is hard to see, but the wing appears to twist very elegantly.

And they just kept making them better and better. Do we need ventilation? What do you think?

Aloha, Barry