Code is, however, considerably more tree-like than stories or sheet music. Sheet music has something resembling minimal control structures, to be sure, and ther

Code is, however, considerably more tree-like than stories or sheet music. Sheet music has something resembling minimal control structures, to be sure, and there are examples of kinds of stories that are more non-linear than usual (and are usually considered mind-benders for that reason). I think that's what the GP is getting at. Even with domain knowledge, really understanding a code almost always requires diverging into other parts of the 'text'. You can defer it if your thought process is structured enough, but you still have to do it eventually.