Metaphors are used to represent the appearence of the snake. They create the meaning of a rough skinned, black and ribbed snake. The snake is similar to the appearence of a rounded tire. This gives the reader an imagination of what the snake looks like. Similes are also used in this poem to give a clear picture of the position of the snake. It appears the black snake looks very light and limp.
The man was sad. The sky was cloudy.
I believe that would be to "pave" a road.
