What structural elements do English and Italian sonnets share?

The Italian sonnet is divided into two sections by two differentgroups of rhyming sounds. The first 8 lines is called the octaveand rhymes:

a b b a a b b a

The English sonnet has the simplest and most flexiblepattern of all sonnets, consisting of 3 quatrains of alternating rhyme and a couplet:

a b a b

c d c d

e f e f

g g