Leonardo believed that all things in nature were governed by
mathematics. Mathematics was of supreme importance and expressed
incontrovertible, universal truth. Knowledge of mathematics was
a prerequisite for understanding the nature of all things. “Let
no-one who is not a mathematician read my principles”, Leonardo
said. Geometry and its actual or potential relationship to
natural forms provided a suitably visual means for the
exploration of mathematical “truths”. According to Leonardo all
things in nature were governed by mathematical rule. Even the
growth patterns and forms of plants were conditioned by
mathematical principals and geometry. On Fol 78v, Leonardo
claimed that each year when the branches of plants have
concluded their maturation, when added together, the sum total
of their cross-section is equal to the cross-section of the
trunk. In the accompanying drawing, he illustrated the principle
by applying geometry to the problem. In the upper diagram, a
tree is shown intersected by a series of arcs