I'm sure you could still fill a good-size poster if you make a nice inefficient representation, like every function call is a separate node in the graph and you

I'm sure you could still fill a good-size poster if you make a nice inefficient representation, like every function call is a separate node in the graph and you include every single device driver even for decades old stuff like tape drives. I agree though, Mother Nature has an inordinate love for making everything a global variable and She definitely hates comments.