Neon Knot

Splashery stretches a drumhead over this Splash's outline, twelve inches across, and finds the ways it can ring. Its lowest is 233.3 Hz, 102 cents sharp of A3, the nearest tine on the comb. The next fifteen are its overtones, and each one draws its own figure: sand gathers on the lines that stay still.

Tap it to make it twist and writhe.

A glowing tube tied in a trefoil knot, the simplest true knot. Tie a knot in a string and join the two ends, and you get a loop that can never be untangled without cutting it; the trefoil crosses itself three times. Mathematicians study knots like this in a field called knot theory.

Tap it and waves of swelling loops run around the tube, lifting and twisting it as it glows pink, then it settles back into its trefoil. Real neon signs glow because electricity makes the gas inside the glass tube shine; pure neon glows red-orange.

Made in Splashery. Its code is MIT.

This link opens it in the Playground. To put it on your own page, add the element and one script tag. Every option.