Ever since I was a kid I've been enamored with the New York City skyline. You see it a lot in these drawings, echoes of the Chrysler building and the streamlined art deco of the city.
Also I like the idea of symmetry, but almost fighting against it, fighting against it drawing these man-made structures that have nothing to do with nature. The hubris! It's can be repetitive, with the windows, but I like how all you need to do is draw a 7 and your brain fills in the rest.