Sure. The first metaphor in "J. B." that really matters is the title. J.B. stands for Job. Job is a character in the Bible, but is also a metaphor himself, for all the unjustified suffering in the world. The God mask mentioned in the prologue has closed eyes, a metaphor for how God seems not to see human suffering. Since "Nickles" is close to "Old Nick," a nickname (ha!) for the devil, this metaphor slides into the symbolic: the devil wears a mask, and humans do not always see him. These guys work at a circus, a metaphor for how the divine has been reduced in stature in recent centuries.