Forth is the language that taught me (among other things) that its possible to break problems into pieces that are too small to understand the whole.

I'm not sure really what to call this other than something along the lines of can't see the forest for the trees. Its the opposite of having functions so large it takes hours to figure out what they do. In this case you have words that you can't figure out what they do for days because the call graphs step across 300 different modules and 10k other words all of which are like "update-pie-with-apples" and comprise two other words "dup pie, apple-pie-update" or something.