Vonnegut's doodles...

An essay by Peter Reed on Kurt Vonnegut's website (http://www.vonnegut.com/artist.asp ... reprinted from Volume 10, Issue No. 1 of the Journal of the Fantastic in the Arts, 1999 Florida Altantic University) says of the felt-tip pen drawings that appear scattered throughout several of Vonnegut's novels:

“the drawings earn their place in the novel, and must be seen as integral to it. Some make graphic the ludicrous disparities that often exist between words as signifiers and what it is they signify. Others simply function as embellishments or even punch lines of jokes. In their almost child-like simplicity of line they have a certain ironic propriety in a novel where the central event is an arts fair. Above all, they are part of-and draw attention to-the seemingly naive, even adolescent, perspective by which Vonnegut deconstructs and demystifies American culture and society in this novel."

The word integral is important - again, these drawings aren't visual 'gimmicks', but part of the text. They serve a function within the text that goes beyond reflecting/reinterpreting the writing. Vonnegut called them "felt tip calligraphs".