See demo on Codepen: https://codepen.io/comehope/pen/PBGJwL
Watch interactive video on Scrimba: https://scrimba.com/p/pEgDAM/cDMyyHv
Read annotated source on Segmentfault(zh-cn): https://segmentfault.com/a/1190000015686159
Inspired by: Irko Palenius https://codepen.io/ispal/pen/mVaaJe