"I think I saw something about..." She scoops out Elias's book again, and flip-flip-flips, and stops. "Here. If I wish for something that my coin of choice isn't big enough to handle, it just doesn't work. If I wish on a pentagon for a chain that I can make coins appear directly on and that will extend invisibility to those coins, then I'll either get that or it won't work." She taps the book a couple times. "I wonder if that's why stars fuck up so much - they are big enough for anything, so people don't have to be thoughtful about the exact wish?"