Editing Piano Phase (section)

==Composition==
{{Unreferenced section|date=November 2016}}
Reich's phasing works generally have two identical lines of music, which begin by playing synchronously, but slowly become out of phase with one another when one of them slightly speeds up. In ''Piano Phase'', Reich subdivides the work (in 32 measures) into three sections, with each section taking the same basic pattern, played rapidly by both [[pianist]]s. The music is made up, therefore, of the results of applying the phasing process to the initial twelve-note melody—as such, it is a piece of [[process music]]. The composition typically lasts around 15-20 minutes.

===First section===
[[File:Piano phase pattern1.png|thumb|right|400px|First motive: 12 semiquavers grouped 4x3]]
The section begins by both pianists playing a rapid twelve-note [[melody|melodic]] figure over and over again in unison (E4 F{{Music|sharp}}4 B4 C{{Music|sharp}}5 D5 F{{Music|sharp}}4 E4 C{{Music|sharp}}5 B4 F{{Music|sharp}}4 D5 C{{Music|sharp}}5). The pattern consists only of 5 distinct [[pitch class]]es.

After a while, one pianist begins to play slightly faster than the other. When this pianist is playing the second note of the figure at the same time the other pianist is playing the first note, the two pianists play at the same tempo again. The process is repeated until the process has gone full circle, and the two pianists are playing in perfect unison.
{{Clear}}

===Second section===
[[File:Piano phase pattern2.png|thumb|left|400px|Second motive: 8 semiquavers grouped 2x4]]
The second pianist then fades out, leaving the first playing the original twelve-note melody. The first pianist adjusts the bottom part to a four-note motif, which changes the pattern to an 8-note repeating pattern. The second pianist re-enters, but with a distinct 8-note pattern. The phasing process begins again; after the full eight cycles, the first pianist fades out, leaving one eight-note melody playing. The section ends at measure 26.
{{Clear}}

===Third section===
[[File:Piano phase pattern3.png|thumb|right|200px|Third motive: 4 semiquavers grouped 2x2]]
The last section introduces the simplest pattern, now in 4/8 meter, built from final four notes of the melody from the previous section,<ref name="Potter">[[#POT00|Potter (2000)]], p.181-188.</ref> and having only four distinct [[pitch class]]es. The other pianist re-enters, the phasing process restarts, and ends when both pianists return to unison. The phase cycle is repeated ''ad libitum'' from eight to sixty times according to the score.
{{Clear}}