From Leonardo’s "Treatise on Painting"

“When you look at a wall spotted with stains, or with a mixture of stones, if you have to devise some scene you may discover a resemblance to various landscapes … or, again, you may see battles and figures in action, or strange faces and costumes, or an endless variety of objects, which you could reduce to complete and well-drawn forms. And these appear on such walls promiscuously, like the sound of bells in whose jangle you may find any name or word you choose to imagine”.