sent out from 2149 and, when it can't be traced back anywhere on Earth, they sense that it reached a different timestream and begin the settlement in that timestream. David R. Slavitt's Walloomsac begins with a description of a river and the stones which it flows over; the narrator is philosophical: "What would be the subject? The water rushing by, looking the same but always different?" Later in the narrative, many lives and changes are discussed. References Time Physics in fiction