Every tone (PC) that is not a chord tone (member of sim chord PCs, in voice 1 by default) is reached/left by a step of the given step size. Args: step-size (int): maximum interval considered a step. voices (int or list of ints): the voice(s) to which this constraint is applied. Optional args: chord-voice (int, default 1): the voice representing the underlying chord. Other arguments are inherited from r-pitch-pitch.