Typically, a shape and purpose of a window are common. It is a mostly square hole to the world. The reason why the shape of windows is square seems to be caused by how to make it. It is easier to make a square window.
A traditional house in Japan has large windows, which are, exactly saying, not a kind of window but a door. You can feel a cool wind in Summer, thanks to the large apertural area. A question is how to get out of the cold.
This challenge was set by the Daily Post.