My dear, the thing is there's what we call "re-engineering"(you may not find this in Google)
It means when you see something somewhere and try to copy or reenact it, it means you understand the thing. Especially when stated in your own words. So for some, when they retype it, they are learning, and most likely will not forget.
....whats the purpose of this section again????....to learn, so it's in Order.
Still confused?