Bob and Alice each have 1000 balls. I add 1000 balls and add 1000 anti-balls. Alice now has 0 balls while Bob has 2000 balls. What happened? Were Alice's ba

Bob and Alice each have 1000 balls. I add 1000 balls and add 1000 anti-balls. Alice now has 0 balls while Bob has 2000 balls. What happened? Were Alice's balls annihilated and Bob picked up the new balls? Did Bob steal from Alice while his balls were annihilated? We just do not know without seeing some extra detail within.