How do you divide a line into three? Or five? Or seven? Is there a simple way to marry harmony and geometry? What is the secret diagram alluded to by writers of antiquity? In this groundbreaking book, philosopher Adam Tetlow reveals the long lost Helicon, the master diagram of the ancient arts and crafts.Watch in astonishment as this magical geometric figure produces simple fractions, musical harmonies, Pythagorean triangles, perspective and more.