Karl Wirsum's mural, Just Us What Past Before Us, is comprised of ten highly stylized, brightly colored images. His figures all take athletic poses, a frequent theme in his illustrations of imaginary characters and superheroes. Similar to this large mural, many of his works capture giants from outer space happily doing mundane tasks. The images bridge the gap between domesticity and super-human powers. Despite their enormous size, the colorful machines blend in with the interior architecture, without becoming daunting or dominating the space. Executed by sign painters who worked from Wirsum's original design, the images range from eight-and-one-half to twenty-three feet in length.

Wirsum was an influential member of the Chicago Imagism group, The Hairy Who, which was formed in the 1960s. Pop Art and the already established Imagism groups from Los Angeles and New York City inspired the movement. They embraced popular culture with cartoon-like satires, characterized by brilliant colors and whimsy congeniality.