Whenever I get across this page I first get very impressed and happy, and then I realise there's no code so I can't use this method myself to make my own maps :(
I've seen that site before but I think all you get is minified js, which isn't terribly helpful if you want to make your own maps to unfold.
[1] https://github.com/philogb/page/tree/gh-pages/myriahedral