Free verse does not "proceed by a strict set of rules … is not a literary type, and does not conform to a formal structure." It is not considered to be completely free. In 1948, Charles Allen wrote, "The only freedom cadenced verse obtains is a limited freedom from the tight demands of the metered line." Free verse contains some elements of form, including the poetic line, which may vary freely; rhythm; strophes or strophic rhythms; stanzaic patterns and rhythmic units or cadences. It is said that verse is free "when it is not primarily obtained by the metered line." Donald Hall goes as far as to say that "the "form" of free verse is as binding and as liberating as the "form" of a rondeau," and T. S. Eliot wrote, "No verse is free for the man who wants to do a good job."