What are the figures of speech used in "Richard Cory," and why did the author use them?

"" byis a short narrative poem
first published in 1897 in Robinson's book . The language tends to be
simple and direct; it uses fewer figures of speech than might be found in Metaphysical or
Romantic poetry. 

Figures of speech are defined as departures from ordinary
language intended to enhance the effects of a piece of writing on the reader. They are normally
divided into "figures of sound" and "figures of thought."

In terms of sound, you will note that the poem is divided into four stanzas, each
comprised of four lines of slightly irregular iambic pentameter. These lines exhibit a regular
rhyme scheme of "open quatrains" (normally abbreviated as "ABAB"). There are
some instances of(repetition of consonant sounds) such as "worked, and
waited."

The main figures of thought we see are amplification
and(overstatement or exaggeration). We can observe both of these in the following
line:

And he was richyes, richer than a king

First, we have the repetition of "rich ... richer." Next,
we have the exaggeration of "richer than a king"; a moderately well-off resident of a
small town is not actually richer than, say, the King of England. Many of the descriptions of
Cory are exaggerated, helping us understand the gulf between him and the other residents of the
town in wealth, social class, and personal lifestyle.