SOCRATES: Then the square is of twice two feet?
BOY: Yes.
SOCRATES: And how many are twice two feet? count and tell me.
BOY: Four, Socrates.
SOCRATES: And might there not be another square twice as large as this, and having like this the lines equal?
BOY: Yes.
SOCRATES: And of how many feet will that be?
BOY: Of eight feet.
SOCRATES: And now try and tell me the length of the line which forms the side of that double square: this is two feet—what will that be?
BOY: Clearly, Socrates, it will be double.