Ghiberti’s The Story of Jacob and Esau, 1435, Boticelli’s The Birth of Venus, 1480, and Raphael’s The School of Athens, 1510-11, evidence those artists’ interests in mathematical perspective, scale, and spatial motifs such as detail in the front, the perceptual blur toward the horizon, the higher horizon line, etc. Color and value are properly applied through painted or actual hills and valleys. This reflects their interests in physics and mathematics.