The most common way, probably, of thinking how to make a window is, first, to decide how big you want it to be; second, to think how you want it to operate (swing out, slide, etc.); and, third, to think how to construct it.
But people who have it in their head to be creative and who design a lot of windowsthat is, architectsthink about windows in more ways than that.
In his building for the Glasgow School of Art, Charles Rennie Mackintosh has provided the architecture students thereand all of usa primer on thinking windows. The two elevations (which is what architects call walls, when theyre talking about what they look like) pictured below are intriguing both because they are stylistically different from one anotherthe differences would make a good essay in themselvesand because each of them illustrates several ways of thinking a window.
Lets look more closely at the elevation on the right. Here, there are four very different windows or sets of windows. In the lower right is the simplest. You could think of it in a couple of ways: either as the space left between two stacks of stone blocksthat would be the constructional way of thinkingor as if it were a rectangular hole that had been cut into a continuous wall. The latter requires a small leap of imagination, because you dont actually make it that way. You dont build the wall, then cut the hole in it. But you can imagine thats how you did it.
The one above it, on the upper right, suggests another imagined way of acting on the wall. Here, instead of cutting into it, you could imagine molding it, pulling it out with your thumbs, as if it were clay. Again, thats not how it was actually made, but it could be how it was thought.
Look at the pair of windows at the upper left and imagine that the glass started out flat at the inside of the opening, or even as a separate sheet running continuously behind the wall. Now imagine that you somehow pumped up the air pressure inside, so that the membrane of glass got pushed out by the pressure, like a couple of balloons. Thats another way of thinking a window.
Ill call all three of these ways of thinking a window plastic, meaning that they involve imagining the materialsstone, glassas uniform and readily manipulable: cuttable, smushable, stretchable, and so on. Architects often think plastically, as well as functionally, operationally, and constructionally. (The more ways you think about a thing, the more likely you are to be creative with it.)