These magnificent drawings demonstrate with complete clarity the structure of the hand, building it up in the manner of an engineer. Leonardo begins with the bones, adds the deep muscles of the palm at lower right, and then the first and second layers of tendons at upper left and upper right. The sequence is continued on the sheet to the right. At the top of the page Leonardo sets out the sequence of drawings of the hand that he intends to make, beginning with the bones and building it up element by element, as seen on the other side of this sheet. The principal drawings here show the articulated bones from four directions, but Leonardo also states the need to depict each individual bone in four views – which would require a further 108 drawings.