Still, what do the multiple strings mean? I was expecting a single string with a complex waveform, with additional pulls changing that waveform. Instead I have a new string every time I pull.
Actually, that's exactly what you are seeing - by pulling the middle sample down to the bottom every time you click, the "spring-like" pull of the sample to the left and the sample to the right (see the Theory section) trigger additional waves that propagate, reflect on the walls, and interfere with the original one.