SOCRATES: Suppose that we fill up the vacant corner?
BOY: Very good.
SOCRATES: Here, then, there are four equal spaces?
BOY: Yes.
SOCRATES: And how many times larger is this space than this other?
BOY: Four times.
SOCRATES: But it ought to have been twice only, as you will remember.
BOY: True.
SOCRATES: And does not this line, reaching from corner to corner, bisect each of these spaces?
BOY: Yes.