Over the weekend I stumbled upon this illustrated Medium post by Alfred Twu comparing sloped and flat roofs. The argument is that these two roof types are coded. In this part of the world, at least, sloped roofs signal low-rise "house" and flat roofs signal big city "high-rise."
I'm not yet convinced of this association with height, or of all the claims made in the article. Did New York City really make the flat roof commonplace in our cities? But the idea that a roofline can trigger certain associations -- or even become divisive -- is a fascinating one.