Recognizing repetition [in sounds]
The curve of the function Sin[x] + Sin[√2 x] shown on page 146 looks complicated to the eye. But a sound with a corresponding waveform is recognized by the ear as consisting simply of two pure tones. However, if one uses the function to generate a score—say playing a note at the position of each peak—then no such simplicity can be recognized. And this fact is presumably why musical scores normally have notes only at integer multiples of some fixed time interval.