Proximity
Al's Sporting Goods
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This website uses a good amount of space that makes the user flow from top to bottom on the page and encourages activity while pushing the eyes down the page.
Contrast
Chick-Fil-A
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This page uses good consumer psychology that uses red for hunger, attaching pictures of food next to big buttons that pop off the page and make it easy for decision making.
Repetition
Springfield Armory
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This webpage uses good practices when it comes to repetition since it has a lot of big square links that are consistently the same shape, color and size that make the user experience a breeze.