See demo on Codepen: https://codepen.io/comehope/pen/mKdzZM
Watch interractive video on Scrimba: https://scrimba.com/p/pEgDAM/cgnk6Sb
Read annotated source on Segmentfault(zh-cn): https://segmentfault.com/a/1190000015089396
Inspired by: Peter Norton https://codepen.io/graphilla/pen/RQzoLO