Gyroid

Splashery stretches a drumhead over this Splash's outline, twelve inches across, and finds the ways it can ring. Its lowest is 539.6 Hz, 53 cents sharp of C5, 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 to make it breathe. Pick a cube or a ball in the Splash tab.

A gyroid is a curving surface that splits space into two tangled mazes of tunnels that never meet. It has no straight lines and no flat parts, and it repeats forever in every direction. Alan Schoen, a scientist working for NASA, found it in 1970. Nature makes it too: tiny gyroid crystals in some butterfly wings give them their shiny green color.

Tap it and it breathes: the surface slides along itself, so one set of tunnels swells while the other narrows, then the other way, and it settles. In the Splash tab, cut it into a cube or a ball.

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.