anchor.diff:  
   Random rand = new Random(47);
   
  -void randomDirection() {
  +Coord randomDirection() {
     int dir = rand.nextInt(4);
     switch (dir) {
       case 0:
  
positive.code:   print("Stop scheduling");
  }
  
  
  void startUpdates(final int movementInterval, final int tailIncreaseInterval) {
  
    stream = new Stream.periodic(new Duration(milliseconds: movementInterval),
        movement);
    stream.listen((ignorethis) {}, cancelOnError: true);
  
    stream2 = new Stream.periodic(new Duration(milliseconds: tailIncreaseInterval
        ), increaseTailLength);
  
negative.code: void increaseTailLength(param) {
    snake.maxSize += 1;
    pauseInMillis = max(pauseInMillis - 2, 350);
    updateStream(pauseInMillis);
  }
  
  
  