It is said that verse is free "when it is not primarily obtained by the metered line." Free verse does not "proceed by a strict set of rules … is not a literary type, and does not conform to a formal structure," but 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 is as equally subject to elements of form (the poetic line, which may vary freely; rhythm; strophes or strophic rhythms; stanzaic patterns and rhythmic units or cadences) as other forms of poetry. 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."