<P> As late as Johannes Kepler (1571--1630), a belief in the geometric underpinnings of the cosmos persisted among some scientists . </P> <P> According to Stephen Skinner, the study of sacred geometry has its roots in the study of nature, and the mathematical principles at work therein . Many forms observed in nature can be related to geometry; for example, the chambered nautilus grows at a constant rate and so its shell forms a logarithmic spiral to accommodate that growth without changing shape . Also, honeybees construct hexagonal cells to hold their honey . These and other correspondences are sometimes interpreted in terms of sacred geometry and considered to be further proof of the natural significance of geometric forms . </P> <P> Geometric ratios, and geometric figures were often employed in the designs of ancient Egyptian, ancient Indian, Greek and Roman architecture . Medieval European cathedrals also incorporated symbolic geometry . Indian and Himalayan spiritual communities often constructed temples and fortifications on design plans of mandala and yantra . </P> <P> Many of the sacred geometry principles of the human body and of ancient architecture were compiled into the Vitruvian Man drawing by Leonardo da Vinci . The latter drawing was itself based on the much older writings of the Roman architect Vitruvius . </P>

Who are the philosophers who believed art was sacred