"I am reminded, now, of Leonardo's advice to painters: You should fix your eyes, he says, on certain walls stained with damp. You will see in these the likenesses of divine landscapes, adorned with mountains, ruins, rocks, extensive plains; and you will see there battles and strange figures engaged in violent actions. For in such walls the same thing happens as in the sound of church bells, in whose reverberations you may find every word imaginable."

Source: Ciaran Carson (2001). “Shamrock Tea”, Granta Books