ASK: Is this a web template or built organically?

[boniface316]

http://www.r2d3.us/visual-intro-to-machine-learning-part-1/

I came across this website and I love how interactive it is. How can I build a website like this?

[cocktailpeanuts]

the site says it's an experiment using D3.

[boniface316]

I didn't know if d3 was a thing. Do you have experience with it?