Contrast can amplify some design elements. By contrasting the size of these two shapes we can make the large shape appear larger and the small shape appear smaller.
"refers to the arrangement of opposite elements (light vs. dark colors, rough vs. smooth textures, large vs. small shapes, etc.) in a piece so as to create visual interest, excitement and drama."
Balance used in advertising. The coke bottles increase and then decrease in size; the largest being in the middle. Folding the ad in half results in the same amount of bottles being seen on each half. The same couple colors are used without giving it a uniform, balanced feel