180 degree rule

During the filming of our prelim we learnt about the 180 degree rule. The 180 rule is a basic guideline in filmmaking which states that the elements in a film should always have the same left/right relationship to each other. If the camera goes over the imaginary axis it is called crossing the line and the new shot is called a reverse shot. 

All coverage should be shot from one side of the imaginary axis because the audience makes a mental note of the actors position in that scene and if the camera crosses the line it temporarily disrupts the audiences viewing experience because they have to re-establish the positions of all the actors/actress in the scene.