Time machines are uncomplicated things. In hundreds of science fiction stories, they have slipped defiantly into the past or slid silently into the future. You know where you are with a time machine. They go forward. They go back. Unless you get caught in a loop. Then you have a problem. Then you're repeating the same day over and over again. But you're a resourceful kind of guy; you figure out a way to break the loop. It's going to take a little time, but you figure time is the one thing you can afford to lose.