A Shakespearean sonnet has a very specific structure. This structure includes fourteen lines of poetry consisting of three quatrains and a rhyming couplet at the end. Each quatrain contains four lines and a couplet has two. The rhyme scheme of a sonnet is ABAB CDCD EFEF GG. Each Shakespearean sonnet has a volta, the turning point, which usually comes after line 8 or line 10. It is often, but not always, triggered by the words but or yet.