180 degree rule

 The 180 degree rule is a camera rule where someone or something is facing another petrson or object. This shot should only be seen in one side. This can be done be putting a line between the two people and crossing this line 

In this image I have placed a pencil as the line between these two toys. As you can see, they are both facing each other

This shot is an over the shoulder shot on the crocodile, this is not crossing the line that I have creating and because of this you can still tell where the lion is looking which is at the aligator.