Reminds me of this [1] I made back in 2005 in Flash action script, thankfully bought back to life by Ruffle [2].

You can fix the ends of the string by pressing space. When both ends are fixed, you can you can drag the beads and release them.

No big deal, but hey I was quite happy with myself back then..

[1] https://www.newgrounds.com/portal/view/267616

[2] https://ruffle.rs/