See demo on Codepen: https://codepen.io/comehope/pen/MXYBEM
Watch interractive video on Scrimba: https://scrimba.com/p/pEgDAM/cEQMJAK
Read annotated source on Segmentfault(zh-cn): https://segmentfault.com/a/1190000015107942
Inspired by: Andy https://codepen.io/kotAndy/pen/ZrdGZr