Inspired by “The Da Vinci Code,” Visconti has unveiled Divine Proportion pens, including a pentagram and five hidden numbers.Pens in limited editions will come in 24-carat gold or sterling silver, and buyers who crack the code will win a golden inkwell. Not fancy enough? At Cannes, Visconti will unveil a Divine Proportion pen encrusted with 618 diamonds and rubies. No price at this point, and you have to supply your own paper. That one is part of Visconti’s HRH line of pens, which Oprah Winfrey has declared the best pen in the world. So far, the Vatican hasn’t weighed in.