Mike Flemming copyrigh
https://poets.org/text/sonnet-poetic-form
Extract:
Sonnet Variations
Though Shakespeare’s sonnets were perhaps the finest examples of the English sonnet, John Milton’s Italian-patterned sonnets (later known as “Miltonic” sonnets) added several important refinements to the form. Milton freed the sonnet from its typical incarnation in a sequence of sonnets, writing the occasional sonnet that often expressed interior, self-directed concerns. He also took liberties with the turn, allowing the octave to run into the sestet as needed. Both of these qualities can be seen in “When I Consider How My Light is Spent.”
The Spenserian sonnet, invented by sixteenth century English poet Edmund Spenser, cribs its structure from the Shakespearean—three quatrains and a couplet—but employs a series of “couplet links” between quatrains, as revealed in the rhyme scheme: abab, bcbc, cdcd, ee. The Spenserian sonnet, through the interweaving of the quatrains, implicitly reorganized the Shakespearean sonnet into couplets, reminiscent of the Petrarchan. One reason was to reduce the often excessive final couplet of the Shakespearean sonnet, putting less pressure on it to resolve the foregoing argument, observation, or question.
How my heart sings 