This is the source for the entirety of helpfulfigures.com. It's generated into static html by Jekyll.

The "content" (basically the stuff found in various html pages in _posts/) is licensed under a Creative Commons Attribution-NonCommercial 3.0 License. Basically, as long as you're not directly making money off it, you're almost certainly fine.

As for the code itself, well, use away, however you want. Attribution would be appreciated but is by no means obligatory!