Y you shall achieve in the midst of its square, as far as its lower half is concerned, after the instructions before given for I; but its upper part you shall divide so that its hither limb shall contain two-thirds, and its farther one-third of the broad standard; and let them slope to either side so that produced they may touch the two angles a. and b.; and the greater circles, by which you are to round out their obtuse or greater angles, make of a diameter as great as a containing side of the square enclosed between the standard and the sides of the great square, as in T was shown; but the diameters of the circles which you apply to the lesser angles, make double the width of the broad standard, as below.