John Cage, Child of Tree (1975)
Child of Tree is a composed improvisation for plant materials. Cage specifies amplified cactus and pea pod shakers as two of ten “instruments” that are to be chosen by the performer. The aleatory is realized on three levels. First by the interpretation of the “score”: the instructions provided are written out in rough-draft-form in Cage’s chicken scratch, with words, sentences and paragraphs crossed out and scribbled over. The difficulty of reading the words and the ambiguity of what is and what is not crossed out adds an element of chance to the construction. Second, by the means of composing the structure: prior to the performance, the performer throws coins and interprets the results (heads or tails) by the oracle of the I Ching (the Chinese Book of Changes). These chance operations determine how many sections the prescribed 8 minutes is to be divided, the lengths of those sections and which instruments are to be used in which sections. And thirdly, aleatory is realized in the performance, which is simply an improvisation. The performer is instructed to “clarify the time structure by means of the instruments,” but even though the performance is completely designed by the performer, an element of chance still exists “because the improvisation can’t be based on taste and memory since one doesn’t know the instruments” (John Cage in an interview, 1982).