Have you ever wondered: How many times can the mirror pool duplicate? Will it ever run out of magic? Will it refuse to duplicate so many? I have a theory. I think that the mirror pool was powered to run just as long as a pony's magic. In other words, I don't think that the pond will ever 'run out of magic'. But I think it might not be able to duplicate the same thing so many times. However, in "Too Many Pinkie Pies", there were so many! But, I still think it has some maximum of power it cannot run at.