Plato, Meno

Socrates
Then let us describe the square, drawing four equal lines of that length. This will be what you say is the eight-foot figure, will it not?

Boy
Certainly.

Socrates
And here, contained in it, have we not four squares, each of which is equal to this space of four feet?

Boy
Yes.

Socrates
Then how large is the whole? Four times that space, is it not?

Boy
It must be.

Socrates
And is four times equal to double?

Boy
No, to be sure.

Socrates
But how much is it?

Boy
Fourfold.