Singer is a symbol of hope throughout the entire narrative: he embodies Mick's hopes that someday she will travel and become a famous musician, he embodies Biff's hope that he will someday find enlightenment, he embodies Dr. Copeland's hope that someday the black race will have justice, and he embodies Jake's hope that soon workers in America will understand that they are oppressed and will fight for their rights. Each character projects these qualities onto Singer, who comes to stand for all that the characters believe in their own minds. This blank-slate quality to Singer is the reason the others believe in him as they would a god: he cannot directly respond to their pleas, but the mere fact that they believe in him enough to confide in him in the first place affords them at least a small measure of peace.
Mick's attempt at a makeshift violin—a clumsy object constructed of an old ukulele and strings from various instruments—is a clear symbol for her thwarted musical ambitions. Mick wants a piano, a radio, and music lessons more than anything else, but she is mature enough to realize that her family's poverty makes these dreams impossible at the moment. On the whole, Mick is constrained by her environment: she is an ambitious, intellectual young girl in a household and a town where there are few people with whom she has anything in common. Her patchwork violin is a poignant symbol of her loneliness, frustration, and sense of futility in the face of these environmental constraints.