I totally didn't realize this until these comments. Neat! I went digging in wikipedia.. the Backpropagation article was created in 2005 and yet the mention of

I totally didn't realize this until these comments. Neat! I went digging in wikipedia.. the Backpropagation article was created in 2005 and yet the mention of association/derivation from the chain rule wasn't mentioned until 2014, through a borrow from the German article https://en.wikipedia.org/w/index.php?title=Backpropagation&oldid=618037812 https://en.wikipedia.org/w/index.php?title=Backpropagation&o...