an incomplete thought

Continuing to read (slowly) Reading Lolita in Tehran. I am in the second section, title "Gatsby". Aside from the amazing fervor The Great Gatsby excites amongst the author's students - so unlike the boredom I recall most of my classmates exhibiting when we were forced to read this book in high school, I started thinking about enduring symbols in American literature. If I mention Gatsby to most of my friends they will reply with the sentence fragment, "Oh, the green light," as if to summarize the entire book (if not all of Fitzgerald's work and that of his contemporaries). Similarly we have the white whale and the scarlet letter from other American classics thrust upon us in high school. What are some other prominent symbols in American lit (not limited to those described by colors)?