When Armand Diangienda picks up an instrument that he has never played, he looks for its hidden rule. There is always a rule, just as in math: a principle that tells him that when he plays one note, or one chord, the next one naturally follows. His fingers mimic how he’s seen others handle the instrument, and then they find the patterns themselves, gaining assurance on the strings, or keys, or valves. “I thank God for that talent, because I can just look at someone playing and I can figure it out,” he said. That skill enabled Diangienda to learn piano, guitar, cello, trombone, and trumpet, and it was crucial twenty years ago, when he started the Kimbanguist Symphony Orchestra, in Kinshasa, the capital city of the Democratic Republic of the Congo.