There's a theorem called the Banach-Tarski paradox that states that given a sufficiently solid ball composed of an infinite amount of non-overlapping points, you can, after partitioning them into a finite amount of subsets, rearrange them in a way so that you ultimately end up with two identical balls of the same size as the original. Remember that an anagram is defined as something that rearranges a word's letters to generate another. It follows that, for this joke's sake, "Banach Tarski Banach Tarski" is an anagram of "Banach Tarski"