What metaphors are used in Shadow and Act by Ralph Ellison?

One major metaphor that is developed in the essay, The World and the Jug, is that the Negro culture being portrayed as functioning within an opaque, jug-like container. Ellison develops this metaphor, suggesting that Negro culture may in reality function within certain limits, but he also maintains that the so-called "jug" is transparent..... that Negroes can see beyond the confines of their experience and come to an awareness and understanding of that which is outside it.