How does the author use foreshadowing in Exercises in Style?

Section III contains some of the most entertaining, the most clever, and the most interesting variations. Among these is "Rainbow", in which some of the juxtapositions between the colorful descriptors and the words they modify are quite funny. The humor and cleverness here foreshadow later Exercises like "Gastronomical", in which everything is described in terms of food. There is the sense in these exercises that they were, for the author, as much about having fun as about making a point.