Institutio Oratoria

On the other hand if we draw a parallelogram measuring nineteen feet by one, the number of square feet enclosed will be no greater than the number of linear feet making the actual length of the parallelogram, though the perimeter will be exactly as that of the figure which encloses an area of 100 square feet. Consequently the area enclosed by four lines will decrease in proportion as we depart from the form of a square.