I was going to suggest it was based on Dan Piponi's slightly more relevant "You Could Have Invented Monads (And Maybe You Already Have)" [1] but after a quick d

I was going to suggest it was based on Dan Piponi's slightly more relevant "You Could Have Invented Monads (And Maybe You Already Have)" [1] but after a quick dig found a comment seemingly by Dan Piponi [2] saying his article was indeed inspired by "You Could Have Invented Spectral Sequences". So I guess either way that's the original spark. 1: http://blog.sigfpe.com/2006/08/you-could-have-invented-monads-and.html http://blog.sigfpe.com/2006/08/you-could-have-invented-monad... 2: http://blog.ezyang.com/2012/02/anatomy-of-you-could-have-invented/comment-page-1/#comment-3465 http://blog.ezyang.com/2012/02/anatomy-of-you-could-have-inv...