A Shakespearean sonnet, for example, is composed of three four-line stanzas, also known as quatrains, followed by a single two-line unit known as a couplet. The quatrains express the content of the poem, while the couplet comments on and summarizes it. Thus, the sonnet form provides a way for the poet to comment on and interpret what he has written about earlier in the poem. Sonnets are unique among poems because they are structured around a central concept. This concept can be anything from a person to a state of mind to a relationship, but it must be treated equally throughout the work. For example, when William Shakespeare wrote about love, he did not compare it to other things such as glory or gold. He compared it to other loves, showing how each one is different yet equal in importance. By analyzing how Shakespeare expressed his ideas through language patterns, we can learn more about human nature and the effect of love on it.