ref: 264e4718c21792ed8ee230d39aa2b9ac88d73b14
dir: /util/faust/square.dsp/
import("oscillator.lib"); freq = hslider("[1]frequency", 440, 0, 20000, 0.0001); amp = hslider("[2]amp", 1, 0, 1, 0.00001); width = hslider("[3]width", 0.5, 0, 1, 0.0000); process = pulsetrainN(2, freq, width) * amp;