REVERSE-ENGINEERING A GENIUS (HAS A VERMEER MYSTERY BEEN SOLVED?)

David Hockney and others have speculated—controversially—that a camera obscura could have helped the Dutch painter Vermeer achieve his photo-realistic effects in the 1600s. But no one understood exactly how such a device might actually have been used to paint masterpieces. An inventor in Texas—the subject of a new documentary by the magicians Penn & Teller—may have solved the riddle.