Well, then I don't get it. The most common windmills have horizontal axes. the only one with vertical axes I've ever seen were built in the US some 20 years ago. and the reason why the stopped building them was that the horizontal kind is simply more efficient.
I have never heard of any windmill with a vertical axis of rotation. Therefore they do not exist, and have never existed, and any suggestion of their existence is part of an evil plot by windmill fanatics to destroy the world.