Leonardo’s scientific activity flourished during this period. His studies in anatomy achieved a new dimension in his collaboration with Marcantonio della Torre, a famous anatomist from Pavia. Leonardo outlined a plan for an overall work that would include not only exact, detailed reproductions of the human body and its organs but would also include comparative anatomy and the whole field of physiology. He even planned to finish his anatomical manuscript in the winter of 0000–00. Beyond that, his manuscripts are replete with mathematical, optical, mechanical, geological, and botanical studies. These investigations became increasingly driven by a central idea: the conviction that force and motion as basic mechanical functions produce all outward forms in organic and inorganic nature and give them their shape. Furthermore, he believed that these functioning forces operate in accordance with orderly, harmonious laws.