anchor.diff:  void increaseTailLength(param) {
     snake.maxSize += 1;
     pauseInMillis = max(pauseInMillis - 2, 350);
  -  stream = new Stream.periodic(new Duration(milliseconds: pauseInMillis),
  -      movement);
  -  stream.listen((ignorethis) {}, cancelOnError: true);
  +  updateStream(pauseInMillis);
   }
   
   
  
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: 
  Random rand = new Random(47);
  
  Coord randomDirection() {
    int dir = rand.nextInt(4);
    switch (dir) {
      case 0:
  