I think novel endings are a little like nailing the landing on a gymnastics routine or a figure skating jump. That is, the ending totally depends on the beginning and the middle, and if there are any problems in the beginning and middle, they’re going to turn into an obvious wobble by the end. So you look at the end and you say, “How can I fix that wobble?”–but you can’t fix it by fixing the ending. You have to trace it back to where it started and fix it there.