A week ago I went on great strobist meetup in Harold Wood Hospital, a derelict hospital near Romford. Within 5 minutes of arriving, when all the other photographers were racing off, I had already spotted my shot next to the makeup room. There were several holes in the walls and I wanted to use these as a frame for the lovely Emma (aka Darke Mort) who didn't need any makeup.
The first series of shots that I took were through a jagged hole in the wall and though I got some nice shots, I was struggling a little to get the right framing. But then we moved to the next room where there was the big square hole in the wall.
The lighting for this couldn't be simpler, the colour of the wall was more or less white, so I pointed an SB28 at the wall in front of Emma at 24mm zoom. This made a nice big soft light source in front of Emma that also threw a little light on the room. Had I used an umbrella as I had in the previous room I would have got a lot more spill on the wall behind and positioning would have been tricky.
Photographing someone through frame is a rather interesting excercise in itself. Apart from useing the frame within the frame, it makes it easier to visualise different compositions. You should try it one day