And yet there is still one on a dark surround, and one on a light surround. Why? Because if the tile in that shadow were in fact in shadow, and reflecting the same amount of light to your eye as the one outside the shadow, it would have to be more reflective — just the laws of physics.
Porque si la baldosa en la sombra fuera de hecho una sombra, y reflejara la misma cantidad de luz a nuestro ojo como la que está fuera de la sombra, tendría que ser más reflectante -son las leyes de la física.