What if? What if there are an infinite number of universes? Such universes, should the exist, would perforce contain an infinite number of Elvis Presleys. Here are a few of them.What if? What if Marcus Garvey discovered and perfected a miraculous new ceramic, "Blackglass", with greater tensile strength than steel, lighter than aluminum, harder than a diamond, and, once fired, almost impervious to heat? What if? What if an obscure writer wrote a handful...