Ever since I first read this on Matt Jones' site, aleatoric has remained in my head and refused to go away. So I'm exorcising it now by posting it here. Aleatoric occurs in many associations on the web (Google lists some 8,940 occurrences): there are aleatoric places ('places decided by chance'), aleatoricity is central to Psychogeography, there is (most famously) aleatoric music ('The term was devised by the French composer Pierre Boulez to describe works where the performer was given certain liberties with regard to the order and repetition of parts of a musical work'), there are aleatoric methods for creating graphics ... The list goes on and on.

Aleatory and Aleatoric — Composition depending upon chance, random accident or highly improvisational execution, typically hoping to attain freedom from the past, from academic formulas and the limitations placed on imagination by the conscious mind. There is a tradition of Japanese and Chinese artists employing aleatoric methods, many influenced by Taoism and Zen Buddhism. In the West, precedents can be found among artists of ancient Greece and later among artists of the Italian Renaissance. Leonardo da Vinci (Italian, 1452-1519) recommended looking at blotches on walls as a means of initiating artistic ideas. Aleatory (methodology) was also employed by numerous twentieth century avant-garde artists. Followers of the Dada and Surrealism (movements) produced numerous examples. Jean Arp (French, 1887-1966) made collages by dropping small pieces of paper onto a larger piece, then adhering them (to) where they landed. André Masson (French, 1896-1987) and Joan Miró (Spanish, 1893-1983) allowed their pens to wander over sheets of paper in the belief that they would discover in those doodles the ghosts of their repressed imaginations. Similarly, Tristan Tzara (Romanian, 1896-1963) created poetry by selecting sentences from newspapers entirely by chance. (adapted from ArtLex)

Jean (Hans) Arp, Collage Arranged According to the Laws of Chance, 1916–17
Torn-and-pasted papers on gray paper, 19 1/8 x 13 5/8" (48.6 x 34.6 cm)
Purchase © 2002 Artists Rights Society (ARS), New York, VG Bild-Kunst, Bonn

This elegantly composed collage of torn-and-pasted paper is a playful, almost syncopated composition in which uneven squares seem to dance within the space. As the title suggests, it was created not by the artist's design, but by chance. In 1915 Arp began to develop a method of making collages by dropping pieces of torn paper on the floor and arranging them on a piece of paper more or less the way they had fallen. He did this in order to create a work that was free of human intervention and closer to nature. The incorporation of chance operations was a way of removing the artist's will from the creative act, much as his earlier, more severely geometric collages had substituted a paper cutter for scissors, so as to divorce his work from "the life of the hand". (MoMA)