Yeah the encyclopedia analogy is actually better than GP probably intended because both encyclopedias and source code can take on a branching, fractal information flow. I obviously don't read an encyclopedia start to finish linearly, but as a kid I would start on a random Wikipedia article that caught my attention, and just keep clicking blue links, backtracking whenever I've gone to far. Reading a new codebase is usually not so deep, but it's a similar process of previous definitions.
I used to do this with the paper encyclopedia too... Id sit on the floor surrounded by books open to a page with slips of paper, pencils and whatever else was around as markers. I'd try to keep track of where i came from so i could backtrack through my side quests.
When tabbed browsing came around it was a relief, the browser did all that for me well enough. Unsurprisingly I frequently find out how many tabs is too many for my current computer (less frequently than 20 yeas ago tho since browsers and computers are a lot better than they used to be.)
