Fixed Form and Open Form

Form is a set of expectations

A form is not decoration. A form is a contract with the reader: it promises a certain number of lines, a certain pattern of sound, and a certain place where the poem will turn. Every promise a form makes can be kept, delayed, or broken — and the keeping, delaying and breaking are where the meaning lives.

The two sonnets

• English (Shakespearean) sonnet — 14 lines, rhyming ABAB CDCD EFEF GG. Three quatrains that usually stack three versions of one idea, then a closing couplet. The couplet is a tiny room: it can seal the argument, undercut it, or refuse it.
• Italian (Petrarchan) sonnet — 14 lines split 8 and 6: an octave rhyming ABBAABBA and a sestet rhyming CDECDE or CDCDCD. The octave states a problem, the sestet answers it. The hinge falls at line 9.

Villanelle

Nineteen lines: five tercets and a final quatrain, on only two rhymes, with two whole lines used as refrains. Because the refrains return whether the speaker wants them or not, the villanelle is the natural shape for obsession, grief, and anything the speaker cannot stop saying. Watch the refrains change meaning as their context changes; the words stay identical while the sense moves.

Blank verse and free verse

Blank verse is unrhymed iambic pentameter — the form of Shakespeare's plays and of Milton's epic. It has a strict metre and no rhyme, so it can sound like heightened speech. Free verse has neither fixed metre nor rhyme scheme; its organising unit is the line itself, controlled by line length, repetition, syntax and white space. Free verse is not the absence of form. It is a form the poem invents once and must then obey.