Scientists at Washington University in St. Louis have created a robot photographer, called Lewis, that is able to wander round a room, pick out faces and snap decent shots.

A small canister with wheels and a video camera for an eye, Lewis seeks bare skin like a Playboy photographer. When it finds some, it uses a number of techniques to determine which skin is part of a face.

It then tries to compose the picture by following the rule of thirds, which suggests that a picture split horizontally and vertically into thirds will have its main points of interest where these lines intersect.