This way reminds the vitruvian mode of defining the circumference first, thence the square as if it were to reflect its main properties: a pathway that will become the main theme, if not the goal of this important reconstruction, leading to the ultimate true design of the “homo bene figuratus”.
It's also to behold that while the unconscious pulsations function is related to the circumference' golden map, it is the 2nd and 3rd circles of the circumference map inscribed in the square to match the conscious breath, as well as the 4th one the bones structure at the shoulders level, likely the most complex and important articulation of the body.Far from being a strain, this adaptation corrects obvious imperfections, besides the positioning of the navel, the better heart and cardiovascular center, the 2nd Golden Circle now tangent to the square, visually highlighting the relationship between the circumference and the square.
As I have implied, It has been likely a deeply instinctive research by the Golden Section lovers, this Ratio between the two basic frames; but it could never succeed so far, for the simple reason that the circumference drawn by Leonardo was wrong, being forced to delimit his imaginary figure, in turn altered for the purpose.
Just a detali: in the image of the heart [PDF 12Mb] the blood red area appears curiously enough framed in a dark shaded halo, which forms nothing less than the popular profile of the hearts, from playing cards to valentines, graciously different from the actual muscular organ. This solution was neither artificial nor obtained on purpose, but the result of an automatic treatment of the cardiovascular center image, after some steps to adapt its saturation and contrast.