" When Leonardo da Vinci wanted to create a whole new style of painting, one that was more lifelike and emotional, he engaged in an obsessive study of details. He spent endless hours experimenting with forms of light hitting various geometrical solids, to test how light could alter the appearance of objects. He devoted hundreds of pages in his notebooks to exploring the various gradations of shadows in every possible combination. He gave this same attention to the folds of a gown, the patterns in hair, the various minute changes in the expression of a human face. When we look at his work we are not consciously aware of these efforts on his part, but we feel how much more alive and realistic his paintings are, as if he had captured reality. "

― Robert Greene , Mastery