But it's not critical for your diagonal to span the entire photo. You can get essentially the same effect even with a partial diagonal, .

This is a fun one. No doubt you've seen photos in which most of the frame is filled with more or less the same thing: a field of grass, a pile of pennies, rocks, fish, stars in the night sky. Such photos truly would be monotonous if that's all they offered, but often, the photographer will incorporate one out-of-place element that attracts your eye like a magnet. With that in mind, this rule says that you should look for photos that are mostly uniform and then with an element that disturbs the natural flow or organization of the scene.

Rules, of course, are meant to be broken. The rule of symmetry is all about capturing the natural symmetry in nature. There are a few ways to do this. You might shoot a scene in which both sides of your photo are essentially the same, for example. Or you might shoot a photo of something that is itself quite symmetrical, like a flower.