To discover the principle for doubling a square
"The slave boy in the Meno dialog is guided by Socrates to discover the principle for doubling a square. He is guided to create a new square that is 4 times as big as the original square, and then divide each of the resulting four squares in half along the diagonal, which results in a square created by the diagonals that is twice as big in area than the original square. The slave boy could look at the result and say with absolute certainty that the resulting square is twice as big in area as the original square, by simply counting the triangles as evidence. He could see the evidence reflecting the principle. He knew the result to be true."
