The text examines the human body's structural elements, focusing on the relationship between circles, triangles, and pyramids in anatomy. It describes the influence of the circle on facial features and morphology, then explains the geometric principles of the triangle and pyramid. These shapes are fundamental in understanding both planar and solid structures.
OF THE HUMAN FIGURE.
the formation of the muscles that move the eyebrows, and extend on the forehead to the shape of aquiline noses; to the roundness of the eyes, without any muscle falling over them, nor any fold in the skin in this place; to the beard of the jaws which extends in width and forms a circle around the face. The figure of the circle also influences the fullness of the neck, which is very fleshy, as well as the junction of the shoulders and the entire head, to the throat under the chin, which is fleshy and surrounded by thick beard, and to a myriad of other parts that take the circle as a principle.
About the Triangle and the Pyramid.
The triangle, the third primitive element of the human body, derives its origin from the ternary number, since it is composed of three lines. Indeed, having arranged three points so that they are equally distant from each other, and having joined them with straight lines, there results a triangular shape which is the base of the pyramid. The triangle is therefore the element of figures on flat surfaces, as the pyramid is in solids.
The pyramid is a solid figure, which rises from a flat surface in such a way that the point is called the cone or summit. The name base is given to the lower part of this figure, from which the size of the pyramid gradually elevates, with the lines inclined in such a way as to form a pyramid enclosed within the contour of three equal sides.