The Diagonal Rule states that a photograph looks more dynamic if the objects fall or follow a diagonal line. The diagonal line doesn't have to be an actual line and it doesn't have to be a straight one. It could be the edges of a river, the top of a forest, or even an imaginary line connecting the different objects in the scene.
One side of the picture is divided into two, and then each half is divided into three parts. The adjacent side is divided so that the lines connecting the resulting points form a diagonal frame. According to the Diagonal Rule, important elements of the picture should be placed along these diagonals. Here are some pictures as examples:
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