See demo on Codepen: https://codepen.io/comehope/pen/oMqNmv
Watch interactive video on Scrimba: https://scrimba.com/p/pEgDAM/cm48rta
Read annotated source on Segmentfault(zh-cn): https://segmentfault.com/a/1190000015853738
Inspired by: Katherine Kato https://codepen.io/kathykato/pen/eevQEJ