Earle Brown's December 1952 is a composition characterised by the use of graphical elements in the score. Part of a 'search for a new notation', it is constructed of 31 rectangles or lines.
Earle Brown later imagined the piece as a sort of Calderesque, musical orrery, a box in which the score's elements would be actualised and motorised, "so that the vertical and horizontal elements would actually physically be moving in front of the pianist", who would interpret them "as they approached..., crossed in front of..., and obscured each other... The performer [would play] very spontaneously, but still very closely connected to the physical movement of these objects."
This piece has involved the construction of such a system in software (and considers hardware implementations, but how metaphorical are Brown's words?) also allowing generative multiple automatic realisations, or variations, of the piece, live and in real-time, using common practice and augmented forms of notation.