This picture shows that no one, even friends, are to be trusted. One must always be watching their back, and their front, to avoid being hurt by others. In Macbeth, Macbeth betrays a number of characters in his quest for the throne, characters that he once considered loyal friends and companions.
A very interesting and somewhat new concept of portrait photography that shows the model holding up a frame, only to reveal the back of their face. It gives off a strong anonymous identity that makes you want to be able to physically walk around and see their face.