svoid test_RenderFrequencySample_SquareWave() {
  var c = complex(0, 1);
  print(angle := c.angle()/twoPi());

  for (frac : countIterator(0.0, 1.0, 0.05))
    print(frac + " = " + RenderFrequencySample_SquareWave().get(c, frac));
}