Actually, they're presented in the book as Contrast, Repetition, Alignment, and Proximity. Williams jokes in the early chapters that she wanted to find an easy

Actually, they're presented in the book as Contrast, Repetition, Alignment, and Proximity. Williams jokes in the early chapters that she wanted to find an easy-to-remember acronym for the four central concepts of the book - and boy did she pick a good one. At least it's memorable.