You can use books to make a book stack. Everyone seems to make them out of wood (us included) and call them a wood book stack. But you could make them out of books. You want books that are the same size, so you could either buy three copies of the same book or you could find three books that are the same size. If they have paper covers on them, be sure to remove the covers and look at the spine of the book. You're going to put the words there, so you want to make sure there aren't any words already imprinted there.