In a poem, how do literary devices affect the readers? In what way?

Poets often
hope to have an emotional impact on readers and to write using language that will be remembered.
In other words, they want readers to feel or respond in certain ways after they read a poem and
to remember that response. To do this, they use literary devices, such as , , and rhyme scheme.
 For instance, in the poem "Dulce et Decorum est," the poet Wilfred Owens tries to
convey to the reader a feeling of horror at the violence suffered by soldiers in World War I,
and he does this, in part, through imagery. Owen doesn't pull back but instead describes the
effect of a mustard gas attack: 

if you could hear,
at...