See demo on Codepen: https://codepen.io/comehope/pen/oyJvpe
Watch interactive video on Scrimba: https://scrimba.com/p/pEgDAM/cqwpQh7
Read annotated source on Segmentfault(zh-cn): https://segmentfault.com/a/1190000015424389
Inspired by: deineko https://codepen.io/deineko/pen/VeMxgr