What are some examples of synecdoche in the great gatsby?

What about Owl-Eyes who acts as the enhancement to the occular imagery in F. Scott Fitzgerald's "The Great Gatsby"? 

Having no real name, this character of synedoche acts as the eyes that perceive the truth about Gatsby.  For instance, when he is in the library at Gatsby's house during a party, he is surprised that the books are real and bound in real leather with actual pages; he has suspected that they, like Gatsby, would merely have the appearance of being genuine.  Also, in the last chapter, Owl Eyes is the only one of the party group to attend the funeral for Gatsby because, as he come "splashing" after Nick and Mr. Gatsby, he wants to meet the father and learn more about Jay Gatsby.  When he talks to Nick after the funeral, he remarks,

Like the billboard that sits overlooking the Valley of Ashes, Owl Eyes sees and understands all.

answer: i declare that all people should be free

explanation: