For Frenkel, the impact of Weil’s Rosetta stone encapsulates the way mathematics develops. Some new ideas emerge as the logical outgrowth of things that are already known. But others — and often the most important ones — are wholly original. |  | “These ideas seem to come from thin air; they’re not tangible, not easily traceable,” Frenkel said. But Weil’s idea, he notes, was more than a dream. “Everybody has a dream,” Frenkel said. “Not only did Weil articulate the dream in the letter, he then converted that dream into something concrete.”