Ask a question about Death Note that's "unanswerable" just to confuse/puzzle everyone and get everyone thinking.
When I say Ask a question about Death Note that's "unanswerable" I mean that ask a question that doesn't make sense because the rules of using a death note haven't explained "enough". (Don't worry if that doesn't make sense.)
Try and see if you can come up with a theory if you like, but it might be a bit hard.