<P> While using the rhyming and metrical structure of the' English' or' Surreyan' sonnet, Shakespeare often also reflected the rhetorical form of the Italian form also known as the Petrarchan sonnet . It divides the sonnet into two parts: the octet (the first eight lines) usually states and develops the subject, while the sestet (the last six lines) winds up to a climax . Thus a change in emphasis, known as the volta, occurs between the end of the eighth and the beginning of the ninth lines--between the octet and sestet . A strong pause at the close of each quatrain is usual for Shakespeare . While he suggests Petrarchan form by placing the chief pause after the eighth line in about 27 or so of the sonnets, in over two thirds of his sonnets he places the chief pause after the twelfth line instead . </P> <P> Iambic pentameter is used in almost all the sonnets, as it is here . This is a metre based on five pairs of metrically weak / strong syllabic positions . Occurring after much metrical tension throughout the quatrains, the couplet exhibits a quite regular iambic pentameter pattern: </P> <Dl> <Dd> / = ictus, a metrically strong syllabic position . × = nonictus . </Dd> </Dl> <Dd> / = ictus, a metrically strong syllabic position . × = nonictus . </Dd>

Where does the turn occur in sonnet 30