| This is some more ideas I found, written ~10 Nov 2000.


Server and client have to have an object in common.

* Client moves the object, tells the server the new (x, y) coordinates.
  PROBLEM: by the time the packet reaches server, it will be out of date

* Instead of sending (x, y) send (dx, dy, timestamp-A)
  Server calculates `delta_time' and uses (dx, dy) to update (x, y)
  PROBLEM: client does not know state of other clients what it sends to
  server could be wrong
  
* Server does above, but if new (x, y) positions invalid, tell the client
  proper (x, y)
  PROBLEM: correction packet will be out of date when it reaches client,
  	   player will see a jerk

* Server does above, but send new (x, y) along with timestamp-A.  Client
  corrects according to correction packet, then moves again following list
  of moves since timestamp-A.
  PROBLEM: player will still see jerk, but less
