https://learngitbranching.js.org
https://github.com/pcottle/learnGitBranching

https://learngitbranching.js.org/?demo

using Raphael.js
https://github.com/pcottle/learnGitBranching/tree/main/src/js/app
https://github.com/pcottle/learnGitBranching/tree/main/src/js/visuals