Preliminary Research: The 180° Rule

'The 180° Rule' ensures that elements within a scene (e.g. people) have the same left/right relationship so that from whatever angle, they appear not to have changed position.  This makes it less confusing for the audience by ensuring continuity.

The diagram to the right shows how two characters will appear on camera. When the camera is in the green (on the right side of the 'line' or 'axis'), the characters appear in the same position, but if the camera is in the red, the characters change position and it would confuse the audience by not having continuity.