Coral Reef

Splashery stretches a drumhead over this Splash's outline, twelve inches across, and finds the ways it can ring. Its lowest is 474.7 Hz, 31 cents sharp of B♭4. The next fifteen are its overtones, and each one draws its own figure: sand gathers on the lines that stay still.

Tap it to open the polyps and let the fish out.

Corals may look like rocks or plants, but they are animals. This reef-building coral is a colony of tiny polyps with tentacles that build a calcium carbonate skeleton; other corals can be soft or solitary. Over thousands of years, corals build reefs. Reefs cover a tiny part of the ocean floor but are home to about a quarter of all the kinds of sea life.

Tap it and the polyps open all over this staghorn coral, like tiny tentacled stars, and six little fish dart out of the reef, hover, turn and dart back in; then the polyps close. Pick a Seed in the Splash tab for a different reef.

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.