See demo on Codepen: https://codepen.io/comehope/pen/EpWagM
Watch interactive video on Scrimba: https://scrimba.com/p/pEgDAM/cZwGRTL
Read annotated source on Segmentfault(zh-cn): https://segmentfault.com/a/1190000015727020
Inspired by: Hubert Kosiacki https://codepen.io/hkosiacki/pen/jaVjEO