See demo on Codepen: https://codepen.io/comehope/pen/ZRjGGy
Watch interactive video on Scrimba: https://scrimba.com/p/pEgDAM/cLQPgSE
Read annotated source on Segmentfault(zh-cn): https://segmentfault.com/a/1190000015376202
Inspired by: Judith Neumann https://codepen.io/judag/pen/eJwzKO