The sestet may have an xyzxyz or xyxyxy pattern. Sonnets with different rhyme schemes in the quatrains of the octet are sometimes called envelope sonnets. The octet typically has a rhyme scheme of abbaabba, although it may also have an abbacddc or abababab scheme.
These lines are split into two sections: an octet, or eight-line section, and sestet, or six-line section. Petrarchan sonnets contain 14 lines written in iambic pentameter, a rhythm that contains five 'feet.' Each foot contains an unstressed and a stressed syllable.
