[marcosdumay]

I recommend anybody to look at Dijkstra's notes on structured programming¹. It's a very worth teaching on how to conduct impartial research and transform a field of knowledge.

But TL.DR. - He got digged plenty of repeating cases of bad code, and proceeded to fix every one of them with very few coherent and systematic changes.

1 - His notes are here: http://www.cs.utexas.edu/users/EWD/ unfortunately, I don't remember what numbers to look.