in a traditional "english" or "shakespearean" sonnet, the first twelve lines are divided into three groups ("stanzas") of four lines each, called "quatrains". the last two lines usually rhyme, and make up a "rhymed couplet" that concludes the poem by summing up the story told in the previous quatrains. in the traditional "italian" or "petrarchan" sonnet, the poem divides into a group of eight lines ("octave") followed by a group of six lines ("sestet").