Which way should a windmill face?

So the wind blows from the south, and we build a windmill facing south. The wind shifts to the north. We can either build a second windmill, or build one which rotates to face the wind. Or we can do this...

As with many technology advances, this started with a simple solution – the idea of turning the windmill on its back! Not only does this make the wind direction irrelevant, but the windmill is pretty compact. Read about it here:

A different kind of windmill

Credit: Mariah Power