Yeah when reading some of Knuth's literate programs, I get the feeling that they are probably the best possible exposition of programs that are not so good to read. :-) That is, the programs aren't structured modularly like good modern programmers would write (encapsulation, separation of concerns, etc.) — instead they freely use global variables, gotos, etc., in the programming style of the 60s with some of Knuth's idiosyncratic improvements. But given that "bad" program, the one with the globals and the gotos, Knuth's literate programming system produces what is probably the best possible exposition of that program — at least for reading as printed material (on paper not on screen).