Keywords: Kepler conjecture 2.jpg en A diagram from Johannes Kepler's 1611 Strena Seu de Nive Sexangula illustrating what came to be known as the Kepler conjecture 1611 http //www math sunysb edu/~tony/whatsnew/column/pennies-1200/cass1 html Johannes Kepler other versions PD-old-100 Johannes Kepler Sphere packings |