The horizontal string is being pinched at the position of the mouse, and the right side is vibrating. The lowest frequency the string can produce is equal to a C2. Try the project here if you want it to sound smoother and be able to play higher pitches: https://turbowarp.org/1296823561/fullscreen?fps=60&limitless The pitch of a string of a consistent material and pressure is 1/L where L is the length of the string. If you pinch a string to half its original length, it will produce a frequency twice its original frequency. This project is essentially a digital theremin using this natural pitch mapping. If you play violin, it might make sense to you. There are multiple advantages of mapping frequencies with this mapping rather than using a linear mapping (where the frequency is linearly proportional to the pixel's location). Notably, infinite frequencies can be played as the string is pinched littler and littler, but they get harder to play in tune. Lower frequencies are given more space, so you can more easily play them in tune.
This uses the SVIE7 engine.