@notepool – current chord
@pcprob – pitch set probabilities for current notepool
@plan/chords – chords in next phrase
@plan/chordDuration – relative durations of each chord in next phrase

@section – to store and recall current section’s progression
@phraselength – length in measures of current phrase)
@tala – will adjust its chord placement to match tala (# of 16ths)
@harmonicrhythm – mean duration for chords in beats (1, 2, 4, 8)
@exiting – exit when required