Windows in Vienna

Early in my trip, the owner of an Indian restaurant in Vienna told my parents and I of a charming little feature of some of the older buildings here: when looking at the exterior of these buildings, each floor has a unique set of window accents. In other words, no two floors have a repeated styling around the windows, and in some cases, the shape of the windows is different as well. Take a look at the photos. I keep trying to Google stuff about this, but all I keep seeing is articles about Windows 7 (which was nicknamed "Vienna" during its development). If anyone has any info about why the buildings were designed this way, let me know. I'd also like to know if there are other cities that have this, or if this feature is uniquely Viennese.