This means that you will not be able to express the ratio between side and diagonal in square by integers. On the other hand, the doubling of a square is so easy that Socrates (in Plato's dialogue "Meno") can even ask an uneducated boy (or slave) to do it. The drawing you see here is a result of the conversation between Socrates and the slave, and this conversation is known in the history of mathematics as the very first geometry-lesson.