How does Derek Walcott use imagery in Omeros?

Walcott makes extensive use of sensory perception throughout Omeros. The pronunciation of Omeros' name is replicated in the "O" sound of the blown conch shell. The blind Omeros perceives his environment by ear. Walcott and his fishermen characters relate to the sea as mother, "mer" in their patois, and her surf writes and erases her message all along the shoreline of their island. Birds proliferate on Maud Plunkett's tapestry and the sea-swift becomes a focal point for several characters, both literally and figuratively. Philoctete's existence is almost defined by his painful wound. Helen's beauty, her proud bearing, and her signature yellow dress turn heads wherever she appears. Aside from these standard appeals to the senses, Walcott's self-reflexive text draws attention to itself. He mentions his thought of a Crow horseman taking shape as he inscribes it in book four; then in the fifth book falling snow and the whiteness of the physical page itself become conflated with "the obliteration of nouns fading into echoes, the alphabet of scribbling branches."