For those who may not know, the reason some buildings in Austin are in the shape of a rectangle with one corner cut off is because of the Capitol View Corridors (CVCs). The state capitol building is just north of downtown Austin. It was decreed years ago that certain corridors would have building height limits to ensure that the dome of the capitol could be seen from certain locations around Austin. Here’s an article about it:
As a result, many buildings have bases of a certain height that take up the entire property, but above that they are built only as far as the CVCs allow for that parcel. So Austin is ending up with a few “canyons” where nothing is built above a certain height.