Notice how the eyes follow you around the room

The phenomenon of the eyes in a portrait "following" the viewer as he/she walks by in an art gallery has been known for generations. A number of articles have been written about this, and the classic example cited in Hals' The Laughing Cavalier.

But the above photo illustrates the point even better, I think. It was taken several years ago, showing Hillary Clinton standing next to one of her celebrity supporters - Natalie Portman. Notice how those eyes follow you around the room...