I noticed something when I watched ESB the other day. I don't know if this has been mentioned before.
In the scene when Zev Senesca is flying his snowspeeder looking for Luke and Han we see out from the front window him going towards a large black rock. Later, when he is saying his last line in this shot, we see that black rock -- from the same angle, but through the back window. It is obviously the same shot, but played backwards.