 The actual residence in Georgetown that is used for the exterior  shots has a rather large yard between it and the infamous steps. The  window that leads to Regans room is at least 40 feet from the top  of the steps. This distance would make it impossible for anyone  "thrown" from the window to actually land on the steps. In the  movie, set decorators added a false wing to the house, so that  Regans supposed window would in fact be close to the infamous  steps.