"LIQUID CONTENT REVEAL" by Ksenia Kondrashova
https://codepen.io/ksenia-k/pen/dyaeGgO
(So cool! In the video, I fork it and add "Knobs" to adjust some of the const values that make it all work, so they can be adjusted right from the preview itself.)

https://twitter.com/CodePen/status/1729982417442922818