Beautiful Music
Lelia and Tony dance together in her apartment to a song that is very beautiful. They are close as they move slowly. It's a symbol of the beauty that exists between the pair as they work to get close after sleeping together. It also symbolizes the beauty of an interracial relationship just before it is shattered by Tony's prejudice.
Allegory for Sexual Liberation
The relationship between Lelia and Tony is an allegory for the sexual liberation and exploration that the Beat Generation sought during the 1950s. More specifically it refers to the lack of depth and communication between two people when they choose to sleep together based on primal needs. Many speak often about the liberating nature of sexual exploration without also sharing the dangers of it, and Cassavetes does so poignantly in this film.
The Met
Ben, Tom and Dennis go to The Met in order to get out and explore New York City, but the trio doesn't go into the museum. It's a symbol that these characters exist on the outside of the structures put into place within their city and society. That they are on the edge of it, rather than participating fully within it.
Overtaken
While singing in a nightclub in Philadelphia Hugh is meant to introduce a group of exotic dancers after he sings, which he believes is degrading to him as an artist. Hugh is then cut off during his first song because he's boring the audience, and doesn't even get the opportunity to introduce the girls as they come on stage and simply take over his set. It's a symbol for how art will be overtaken for entertainment because it is more about keeping the paying customers happy than expresses meaning.
Ben's Trumpet
We only see Ben once in the film with his trumpet. He is a musician and this is his instrument. When we do see it, it symbolizes that he is not doing anything with it. That belief and hope will not substitue for actually doing it. So, when he blows into his trumpet and nothing comes out we see that he doesn't have control over who he says he wants to be.
