The Ninth is an unusual symphony. The scheme of two slow outer movements and two fast ones in the middle is not in accordance with tradition. The keys of the four movements - D major, C major, A minor, D flat major - are at best vaguely related; nor did Mahler specify the key of the Ninth Symphony. The free, open form of the individual movements with their broadly arching structures is also confusing. Adorno once remarked that one must listen to this symphony "from the bottom to the top", ignoring formal expectations and concentrating on the individual motifs which develop, "as with a narrative when one does not know how it ends." Certain commentators have seen a novel-like structure in Mahler's symphonies, and a narrative model must be applied to the Ninth in particular - one that ends openly and uncertainly instead of affirmatively in a recapitulation