Patterns from the Game of LifePart IV: Ostinato Polemicofor piano 4-hands[4:26]This is an addendum to my "3-volume" set of music evolved from John Horton Conway's Game of Life starting configurations. It is the only one based on a single source graph and realized as a single movement. The graph is a 1074x74 unit oscillator Herschel Loop 2, found in 2004, discoverer unknown.
Its long dimension comprises twenty 50-unit sections, framed altogether by two of 36 units. Each section contains constant material (horizontal/ vertical unit squares consistently filled) and variable material (squares unpredictably filled or not) in roughly half/half proportion.
Translating the graphic X/Y to musical Time/Pitch, I have positioned the image in two mutually perpendicular rotations, with 74 then demarking either the vertical or the horizontal. In the former case, with a keyboard- wise 74-pitch spectrum fitting standard piano range, initial mapping to musical parameters could proceed directly. In the latter case, with its implied pitch spectrum spanning fully a dozen piano widths, I opted to separate the member sections, transposing each (its span now within five octaves) independently to usable range.
In the result, rotations applied: at 0 degrees, to sections A,C,E,G,I and their variants; at 90 deg, to sections B,D,F,H,J and theirs. The groups relate as X/Y swaps, as their source graph's entire second half (reading in either orientation) is the horizontal/vertical mirror image of the first. I have named its sections (A'-J', the last 10 of 20) in reverse order to associate the reflections. Additionally, I have flagged all non-varying material by casting its noteheads in a red diamond glyph. (These are not harmonics.)
Note re performance of dynamics: In the 5/8 sections (2+3 vs 3+2), metric accent must pit the stability of beat 1 (agreeing always) against the conflict of beat 2 (agreeing never). In the intervening sections they must join instead to navigate perpetually changing meter.