[yakubin]

I don't know about Python, but this description of coroutines, the general concept, doesn't seem accurate to me. They most definitely cannot be executed in any order. They also have nothing to do with multithreading whatsoever. Lua has the most honest-to-god implementation of coroutines I know of, so I'd suggest looking at that. I've seen the word "coroutines" used in some weird way suggesting multithreading, which probably means Python used them to fake multithreading, but the idea originally has nothing to do with it. The idea actually started out as a way to better structure an assembly program in 1958: <http://melconway.com/Home/pdf/compiler.pdf>.