This figure is called the plenary figure because it is composed of a circle, a square and a triangle, all equivalent in capacity. We also call it the plenary figure, because the circle, the square and the triangle all share one center, and inasmuch as these figures are general to all figures, just as all the elements are made of simple elements, so likewise, all compound figures, be they natural or artificial, descend and are derived from the circular, square and triangular figures, as for instance the human form, or the shape of a shield in which some parts signify the circle, others the square, and others the triangle.

To draw this plenary figure, first draw the triangle, then the square, and then the circle, so that all 3 figures have the same center and each one is centered on the others.