As American troops made their way across Europe and the Pacific on their way to defeating the Axis, they were joined by someone else who seemed to follow them everywhere: Kilroy.  No one is exactly sure who Kilroy is, but there are pictures, and plenty of them—all of them cartoons.  Kilroy was a cartoon of either a bald or a balding man peering over a wall or a fence.  You can see his fingers on the wall, and his cartoonishly large nose stretches even farther than his fingers.  Invariably scrawled beneath this drawing came the legend “Kilroy was here.” Kilroy was a meme that predates the internet, and even the very existence of the word meme .  It was easy to spread around, since anyone could copy the simple phrase, and you didn’t need especially strong art skills to copy the cartoon.  For much of the mid-20th century, Kilroy seemed to be everywhere. Kilroy was in the Vietnam War (left), and earlier in Europe during World War II (right). K...