Drag the top. This simulation was made using my already made string physics, twang, and applying restrictions on length using inverse trig functions and trig. This project is my dream project, since it uses two of my favorite things: trig, and springs. Adjust the length variable to the desired length you want. Enjoy! (Oh, and also, this was coded without any help from anybody. I think that's amazing because many people say strings are hard to replicate :)
