I don't see one anywhere. I think, generally, game mechanics aren't copyrightable, but the text of the game is. So if you wanted to make a game that played the same, I believe that would be legal, as long as you didn't copy the text of the rules. And I think people own their own card designs and can copyright them however they want. I'm not a lawyer, though, and you shouldn't take this as legal advice. Anyone who knows better, please correct me.
