Wikipedia
Anaklasis is a musical composition for 42 string instruments and percussion, composed in 1960 by the Polish composer Krzysztof Penderecki (b. 1933). It was first performed at the Donaueschingen Festival in West Germany in 1960. At this first performance, it was well received by the audience who demanded an encore.
The title of the piece, Anaklasis means "Refraction of Light". This idea is expressed through the continuous modulation of timbre in the piece. Additionally, Anaklasis is a metrical term used in Greek poetry. Penderecki's biographer, Wolfram Schwinger noted that, "Penderecki has indeed admitted, in his programme note for Donaueschingen 1960 when Anaklasis was first performed, that this metrical definition inspired the rhythmic procedure of the central section, and led to the ideas of rotation and arhythmical progressions as factors governing the rhythms generally."