I can’t remember it verbatim, but the jist goes something like this:
A smart man can look at a watch and know, that inside that watch are gears that make the hand behave in the way that they do. A smarter man can look at a watch and imagine a way to set up those gears to make the watch behave the way that it does. But even if he does, that does not mean that is the same design used in the watch he is looking at.