Arthur: So, a totem. It's a small object, potentially heavy, something you can have on you all the time...
Ariadne: What, like a coin?
Arthur: No, it has to be more unique than that, like - this is a loaded die.
[Ariadne reaches out to take the die]
Arthur: Nah, I can't let you touch it, that would defeat the purpose. See only I know the balance and weight of this particular loaded die. That way when you look at your totem, you know beyond a doubt you're not in someone else's dream.