His basic motifs are framed by his interests in the world of visual phenomena. It is the world of outsider art—the self-taught artist, the insane, the folk artist. It is a world filled with popular commercial images and products, especially toys, games, puppets, and dolls. These materials exerted a great influence on the Chicago Imagist artists, the group in which Wirsum evolved artistically and intellectually.
In this painting the baseball player, dressed in black, blends in with the black background, producing an overall impression of pictorial flatness. The Mexican setting, referred to in the title Looking at a Curve Ball in Cuernavaca, is reflected in the decoration of the baseball bat, which resembles a pre-Columbian flint, and in the markings on the athlete's costume, which are reminiscent of iconography of a pre-Spanish ballgame.