Ce that the cube is for the man (Geb), the circle is for the woman (Nut).
« Rubens, in his theory of the human figure, claims that the cube or square is the element of the heroic or athletic form, which suits man. It can not be denied that, either in the general form, or in the outline of the features of detail, and in all the ordinary and natural attitude of a strong man, there is a certain square cut and angular; that the sketch, instead of a line followed and flowing, presents interruptions, caused by the bones which advance, by the muscles and the tendons which separate from each other, and by the veins which cross them . It is especially when a man makes efforts that it becomes sensitive. Because, in the perfect rest, the sketch line softens "(British Library, 1807, p. 342-343). Rubens further says that: " the circle is the second primitive element of the human body: it draws its origin from unity, that is to say, from the point which is its center, which produces the circle in the surfaces, and the globe in the bodies; unity and simplicity constitute its existence. It is from this circle or from this perfect globe that derives everything that looks at women, or everything that is round, flexible, tortuous, curved. "(Theory of the human figure, P. 6).