# Institut for Matematik

One may state the famous Banach-Tarski Paradox as follows: Let $B$ be the unit ball of $\mathbb{R}^3$. Then there is a partition of $B$ into five disjoint pieces such that the pieces, after suitable rotations, can be reassembled into two identical copies of $B$. In other words, two people sharing a watermelon can each get a whole watermelon.