A villanelle is one of the more complex forms. It is written in five tercets, in which the first and last lines of the first stanza alternately appear as the last lines of the subsequent stanzas, with a final quatrain repeating both lines together as the last two lines. There are only two rhymes through the whole poem, the tercets rhymed aba and the quatrain abaa, and the lines usually in iambic pentameter.
William Empson's introduction to his villanelle, 'Missing Dates', admits how rigid the rules are (and that his has a "stiff" quality") but points to Auden's naturalistic use of the form. Anne Ridler, however, in introducing her 'Villanelle for the Middle of the Way' points out that "to use very strict form is a help, because you concentrate on the technical difficulties of mastering the form, and allow the content of the poem a more unconscious and freer release". Her poem demonstrates this, with its looping meditation returning on itself just as the refrain lines do.