Really? We had informal flood fill competitions in my high school... If you understand recursion, it's easy. If you don't... there's so many other things tha

Really? We had informal flood fill competitions in my high school... If you understand recursion, it's easy. If you don't... there's so many other things than flood fill you just can't do. And the generalization of saying "oh, that's just a work list" is easy and enables even more things.