Dr. Seuss Books and Characters/Yooks and Zooks

Yooks and Zooks are characters in The Butter Battle Book, by Dr. Seuss. Yooks and the Zooks live on opposite sides of a long curving wall, fairly similar to the Berlin Wall. The Yooks wear blue clothes; the Zooks wear orange. The main dispute between the two cultures is that the Yooks eat their bread with the butter-side up, while the Zooks eat their bread with the butter-side down. The conflict between the two sides leads to an escalating arms race, each competing to make bigger and better weapons to outdo the other, which results in the threat of mutual assured destruction.