Words have always played a central role in Barry Duncan’s life. He’s worked in bookstores for more than 40 years, reads often, and has tried his hand at writing novels, children’s books, song lyrics, and plays. But it wasn’t until he stumbled onto the book “An Almanac of Words at Play” that Duncan realized words could go backwards. The discovery, which he made in the early 1980s, set him on a course he would follow for decades. For fun, and then out of habit, he began reversing words he saw…