With your indulgence I have two more. One is a frame within a frame and the other uses the frame and depth of field to introduce perspective on the shot.
frame within a frame:
and a forced perspective (or maybe I'm just showing off my daughter.. LOL):
edit: I just went back to make sure the links worked and you can access my snapshots. I think the first one could actually be a frame within a frame within a frame. ; )
one more edit: I probably should have straightened out the shot so the parallel lines of the building line up with the frame border. Thoughts?
last edit I promise: OK.... the window frame is parallel to the snapshot frame. I think that is best.