How does use imagery in Surrealism?

According to the text, surrealists incorporate nature-related images in their poetry. These generally take one of two forms: isolated images representing various aspects of nature, or larger images of nature's elements. Both types can be seen in Eluard's poem "You Rise Up." An example of the first type appears halfway through the poem when the poet writes, "You sing night hymns on the strings of the rainbow." A rainbow is a positive symbol of nature, which is consistent with the overall tone of the poem, in which Eluard sings the praises of women.