You do have to claim you thought of it on your own, just a lot later, true - but that's trivial to do, and impossible to disprove. For example, it's perfectly

You do have to claim you thought of it on your own, just a lot later, true - but that's trivial to do, and impossible to disprove. For example, it's perfectly okay to patent an idea in use a thousand years ago, nowadays, as long as most people in that field haven't heard of it; thanks to recently truly perverse judicial decisions.