Editing Aleatoric music (section)

===Modern usage===
The earliest significant use of aleatory features is found in many of the compositions of American [[Charles Ives]] in the early 20th century. [[Henry Cowell]] adopted Ives's ideas during the 1930s, in such works as the ''Mosaic Quartet'' (String Quartet No. 3, 1934), which allows the players to arrange the fragments of music in a number of different possible sequences. Cowell also used specially devised notations to introduce variability into the performance of a work, sometimes instructing the performers to improvise a short passage or play ''ad libitum''.{{sfn|Griffiths|2001}} Later American composers, such as [[Alan Hovhaness]] (beginning with his ''[[Lousadzak]]'' of 1944) used procedures superficially similar to Cowell's, in which different short patterns with specified pitches and rhythm are assigned to several parts, with instructions that they be performed repeatedly at their own speed without coordination with the rest of the ensemble.{{sfn|Farach-Colton|2005}} Some scholars regard the resultant blur as "hardly aleatory, since exact pitches are carefully controlled and any two performances will be substantially the same"{{sfn|Rosner & Wolverton|2001}} although, according to another writer, this technique is essentially the same as that later used by [[Witold Lutosławski]].{{sfn|Fisher|2010}}{{Unreliable source?|date=June 2010|reason=This is a blog. Does it really stand comparison with an article in the New Grove? On the other hand, does this mean that Lutosławski's usage is also not aleatory?}} Depending on the vehemence of the technique, Hovhaness's published scores annotate these sections variously, for example as "Free tempo / humming effect"{{sfn|Hovhaness|1944|p=3}} and "Repeat and repeat ad lib, but not together".{{sfn|Hovhaness|1958|p=2}}

In Europe, following the introduction of the expression "aleatory music" by Meyer-Eppler, the French composer [[Pierre Boulez]] was largely responsible for popularizing the term.{{sfn|Boulez|1957}}

Other early European examples of aleatory music include [[Klavierstücke (Stockhausen)#Klavierstück XI: polyvalent structure|Klavierstück XI]] (1956) by [[Karlheinz Stockhausen]], which features 19 elements to be performed in a sequence to be determined in each case by the performer.{{sfn|Boehmer|1967|p=72}} A form of limited aleatory was used by [[Witold Lutosławski]] (beginning with ''Jeux Vénitiens'' in 1960–61),{{sfn|Rae|2001}} where extensive passages of pitches and rhythms are fully specified, but the rhythmic coordination of parts within the ensemble is subject to an element of chance.

There has been much confusion of the terms aleatory and indeterminate/chance music. One of Cage's pieces, ''[[HPSCHD]]'', itself composed using chance procedures, uses music from Mozart's ''Musikalisches Würfelspiel'', referred to above, as well as original music.