Lego towers only go so high before they start to bend... then they smash to the floor in a satisfying manner whereupon there will be at least 4 bricks that go under the piano, 19 under the table, 3 where they can't be found except by bare feet and one that is never seen again. You can always guarantee that this one is the one you require to build Hogwart's Castle and no other brick can replace it.

LTS