Do not imagine the Mona Lisa with a mustache! If you failed to carry out this instruction, it is because your power of visualization is so strong that it takes any suggestion, positive or negative, and turns it into an image. And as the maestro emphasized, “the thing imagined moves the sense.” If you think you cannot visualize. Chances are you answered these questions easily by drawing on your internal image data bank, the occipital lobe of your cerebral cortex. This data bank has the potential, in coordination with your frontal lobes, to store and create more images, both real and imaginary, than the entire world’s film and television production companies combined.
From How to think like Leonardo da Vinci, by Michael J. Gelb, published by Delacorte Press, 1998.