There are two basic approaches the poet can take. When using literal language, youre telling it how it is, as truthfully descriptive that langauge is capable of being. Wild as the images are, they arein the internal realm of the poem itselfquite literal. Sorescus speaker is not saying, I was protected as a tortoise in a shell. The speaker of the poem had the shell, and made armour of it.
Figurative language uses comparisons in a variety of ways to create images.
Two frequently used aspects of the figurative include the metaphor and simile, which have their own headings. A comparison not using like or as. Robert Frost suggests that poetry is essentially a way of saying one thing and meaning another, saying one thing in terms of another. Considering metaphor is one of the prime strategies of contemporary poetry of all types, theres tons of examples. Remember that poetry, up until about 120 years ago, was mainly an oral form of literature, spoken aloud.