'Leonardo Da Vinci spent a lifetime trying to paint one. Scientists and mathematicians have puzzled for centuries over what makes one, while cosmetic surgeons have amassed fortunes striving to create one. And Florence Colgate? Well, she simply has one. The 18-year-old student is blessed with what is described as the perfect face. It matches an international blueprint for the optimum ratio between eyes, mouth, forehead and chin, endowing her with flawless proportions. In theory, that needn't necessarily cause her to appear anything more than symmetrical (in which department, incidentally, she is also faultless). But the blue-eyed blonde's mathematical dimensions have...