If there a manual option when you were playing duelist kingdom to do whatever you want, it would work. However, the game only lets you play by the current and obscure rules. Not the rules that were so loose, you could interpret them however you want. I wish I could play Duelist Kingdom style without jailbreak or hacking, but it is not possible. Maybe they might add a function like that to make it more like Dueling Network (Rest in Peace). But, for now, we cannot do it. I would like to at least be able to play by those rules ignoring the BS. Such as being able to fuse any two monsters or play a labyrinth duel by summoning Labyrinth Wall in attack position. But again, not possible without coding, jailbreak, or hacks. You could technically recode the entire game to make this possible. However, you could only play by yourself unless someone else had the same program. I think that this would be a great function and would make people feel a little less sad that Dueling Network is gone. It would give people freedom to use any card they want, even if it is not in the game, make up rules, think of new games based off of Duel Monsters, let people teach each other how to play, let people simulate life points more easily, and simulate almost any duel.