Editing Aleatoric music (section)

==Open form music==
[[Open form]] is a term sometimes used for 'mobile' or 'polyvalent' [[musical form]]s, where the order of [[Movement (music)|movements]] or [[Section (music)|section]]s is indeterminate or left up to the [[Musician|performer]]. [[Roman Haubenstock-Ramati]] composed a series of influential "mobiles" such as ''Interpolation'' (1958).

However, "open form" in music is also used in the sense defined by the art historian [[Heinrich Wölfflin]]{{sfn|Wölfflin|1915}} to mean a work which is fundamentally incomplete, represents an unfinished activity, or points outside of itself. In this sense, a "mobile form" can be either "open" or "closed". An example of a "dynamic, closed" mobile musical composition is Stockhausen's ''[[Zyklus]]'' (1959).{{sfn|Maconie|2005|p=185}}