anchor.diff:    num _lastTimestamp = 0;
     int _rightEdgeX;
     int _bottomEdgeY;
  -
  -  Keyboard _keyboard = new Keyboard();
   
     Snake _snake;
     Point _food;
  
positive.code:     _body.removeLast();
    }
  
    void _checkInput(Keyboard keyboard) {
      if (keyboard.isPressed(KeyCode.LEFT) && _dir != RIGHT) {
      _dir = LEFT;
      }
      else if (keyboard.isPressed(KeyCode.RIGHT) && _dir != LEFT) {
        _dir = RIGHT;
      }
      else if (keyboard.isPressed(KeyCode.UP) && _dir != DOWN) {
        _dir = UP;
      }
      else if (keyboard.isPressed(KeyCode.DOWN) && _dir != UP) {
        _dir = DOWN;
      }
    }
  
  
negative.code:       _lastTimestamp = delta;
        clear();
        drawCell(_food, "blue");
        _snake.update();
        _checkForCollisions();
      }
  
  