Lines on the red cup
The red solo cup is universally identifiable as a tool used by frat boys and college kids all over the US for parties. What most casual observers often miss is the lines on the side of the cup and for what they were originally intentioned. The cup itself has gone through a few iterations before finally settling on the now ubiquitous red color and lines across the side. The lines were introduced as a way of measuring how much of a drink you consume. The bottom line measures out one ounce, meant for drinking hard liquor, the next is for whine and the top-most for beer.