Rules are anathema to art. Repeat that. It includes the notorious rule of thirds, originally invented by a 19th century British painter to explain his own compositions, then weirdly adopted by photographers searching for easy guidance. Same goes for rules about balance, harmony, symmetry, asymmetry, odds, color matching, tonal adjacency, dimensions, and all others either extant or yet to be sprung on us. With enough of them, we can reduce art to catechism, and then safely and prophylactically remove the independent genius of the artist, leaving a very pleasing photographic equivalent of painting by numbers. Those who create by rule create not much more than confusion.