What metaphors are used in To Be a Slave by Julius Lester?

In the following passage, an ex-slave describes the frustration experienced by newly emancipated slaves. These slaves faced restrictive laws, economic oppression, and the Ku Klux Klan—in terms of a metaphor: Two snakes full of poison..."The snake called slavery lay with his head pointed south and the snake called freedom lay with his head pointed north. Both bit the nigger and they was both bad."