gong + kempul slendro, piano, slenthem pelog, vibraphone, & bonang panerus slendro,
"Gatra" is a composition by Jay Afrisando using a combination of non-deterministic L-System (a formal grammar, one of the algorithmic methods) and the human touch (from the composer). The L-System was developed by Aristid Lindenmayer and firstly used by botanists and computer scientists to mathematically model growth processes of living organisms.
In Javanese, gatra means embryo or, in gamelan, the smallest and flexible musical unit. The music is composed by developing 'an embryo' into certain shapes through a set of production rules or rewriting rules. The non-deterministic factor results different products in each developed musical 'embryo'. Because of this procedure, the product of L-System creates fractal, the condition which a larger entity (a larger musical unit) resembles a smaller entity (a smaller musical unit) and vice versa, although it does not always appear as a same-similarity. This fractal phenomenon also happens in a relationship of gatra (a smaller musical unit) and gendhing (a larger musical unit) in Karawitan.
Performed at October Meeting 2016, Yogyakarta, ID on 15 October 2016.
Ensemble Kyai Fatahillah gamelan
You can listen to all the performed pieces at the festival in the Trace21 website.