I've been puzzled by this as well. I think the book is called SIDESHOW because, being Rea's second book, it can be seen as a "secondary production", something extra. This idea of an 'aside' is expressed by the bony brackets around the V on the plate. The food on it may refer to a certain attraction of the sideshow: the 'girl show' or revue. The three items appear to form the outline of a dancer's foot, and their 'boneness' can convey something more about the rousing nature of this particular show––and this particular book. However, since it is just an ordinary foot, and no slender ankle or high heel is indicated, I think what is really shown here is the effect of the cartoons in SIDESHOW: a kick in the funny bone.
