Don't give me that "butterfly" jazz. It's a bat and you know it.After 9/11, a photographer learned that people were seeing an unexpected image in one of the photos he'd taken of the burning World Trade Center. When he examined the picture he saw it, too. "The image I saw was distinct," he later wrote. "Eyes, nose, mouth, horns." There, in the contours of the smoke, he found the face of Satan.

The face, Jesse Walker writes, was the result of pareidolia, a phenomenon in which patterns are perceived as meaningful shapes or sounds. It is pareidolia that allows us to see a man in the moon, to hear a satanic incantation when "Stairway to Heaven" is played backward, or to conjure the image of your subconscious choice while taking a Rorschach test. Indeed, pareidolia makes the whole world a Rorschach test.