I read this article two weeks ago (I would swear that it was on HN) and I was driving yesterday in the south of France, among plenty of wind turbines.

I was recalling the article as I was driving and -- surprise -- a two-bladed one appeared suddenly (two, actually).

This was the only time I saw two bladed wind turbines and could makr intelligent comments about why 3 and not 1 or 2 :)

So thank you!