See demo on Codepen: https://codepen.io/comehope/pen/VdbGvr
Watch interractive video on Scrimba: https://scrimba.com/p/pEgDAM/cky6wfa
Read annotated source on Segmentfault(zh-cn): https://segmentfault.com/a/1190000015283286
Inspired by: Ana Tudor https://codepen.io/thebabydino/pen/bdfjc