An option to set delay=100 in `setInterval` could be interesting to reveal the surprisingly angular shape of the string, at least until non-linear coupling rounds it out.

Thanks for the comment! I actually remember (many years ago) looking at animated solutions of the wave equation and thinking they couldn't be right because of that exact phenomenon. A main point of this animation is to keep it as simple as possible, so I'd prefer not to add any controls. I do have a more full featured wave explorer where you can create that type of effect, though: https://observablehq.com/@mcmcclur/one-dimensional-waves

Yes, your wave explorer treats this very well. I first learned about this surprising solution when creating a class on the physics of music: https://images.slideplayer.com/15/4694044/slides/slide_23.jpg I did all of my teaching animations in java back then, but observable is such an improvement.