of the first stanza serves as the last line of the third and fifth stanzas. The rhyme-and-refrain pattern of the villanelle can be schematized as A1bA2 abA1 abA2 abA1 abA2 abA1A2. Here, "a" and "A" lines rhyme, and A1 and A2 indicate two different refrains which are repeated exactly. The villanelle has no established meter, although most 19th-century villanelles have used trimeter or tetrameter and most 20th-century villanelles have used pentameter. Slight alteration of the refrain line is permissible. Effect With reference to the form's repetition of lines, Philip K. Jason suggests that the "villanelle is often used, and properly used, to deal with one or another degree of obsession" citing Sylvia Plath's "Mad Girl's Love Song" amongst other examples. He notes the possibility for the form to evoke, through the relationship between the repeated lines, a feeling of dislocation and a "paradigm for schizophrenia". This repetition of lines has been considered to prevent villanelles from possessing a "conventional tone" and that instead they are closer in form to a song or lyric poetry. Stephen Fry opines that the villanelle "is a form that seems to appeal to outsiders, or those who might have cause to consider themselves as such", having a "playful artifice" which suits "rueful, ironic reiteration of pain or fatalism". (In spite of this, the villanelle has also often been used for light verse, as for instance Louis Untermeyer's "Lugubrious Villanelle of Platitudes".) On the relationship between form and content, Anne Ridler notes in an introduction to her own poem "Villanelle for the Middle of the Way" a point made by T. S. Eliot, 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". In an introduction to his own take on the form, entitled "Missing Dates", William Empson suggests that while the villanelle is a "very rigid form", nonetheless W. H. Auden—in his long poem The Sea and the Mirror—had "made it sound absolutely natural like the innocent girl talking". Examples "Do not go gentle into that good night" by Dylan Thomas. "Halt, Dynamos!" by Francis Heaney, in his Holy Tango of Literature. (A parody of "Do not go gentle into that good night.") "The Waking" by Theodore Roethke. "Mad Girl's Love Song" by Sylvia Plath. "One Art" by Elizabeth Bishop. "If I