What purpose does synesthesia serve in literature? What does Syllepsis tell us about an author’s work?

Nick: What purpose does synesthesia serve in literature? What does Syllepsis tell us about an author’s work?
How does it help illuminate meaning in literature. For both Synesthesia and Syllepsis.
I need to do a Literary Term Presentation on Synesthesia and Syllepsis. I’m stuck on answering the following questions for both terms. What purpose does the lit device serve? What does it tell us about the work?How does it help illuminate meaning?

Answers and Views:

Answer by Carpetbomb
is that another homework question?