Fermat's Last Theorem

Imagine you're stacking blocks in a pyramid shape. You know that if you stack 1 block on top of 2 blocks, you get a 3-block tall pyramid. But what if you tried stacking 1 block, 2 blocks, and 3 blocks to make a 4-block tall pyramid?

Fermat's Last Theorem tells us that there's no way to stack cubes in such a way that the height of the pyramid equals the cube of the total number of blocks. The technical term is xⁿ + yⁿ = zⁿ for n > 2.