code: func NewOsc(shape WaveType, hz float64, fs int) *Osc {
  	return &Osc{Shape: shape, Amplitude: 1, Freq: hz, Fs: fs, phaseAngleIncr: ((hz * TwoPi) / float64(fs))}
  }
docs: // NewOsc returns a new oscillator, note that if you change the phase offset of the returned osc,
  // you also need to set the CurrentPhaseAngle