anchor.diff:    StageXL.Vector downDirection = new StageXL.Vector(0, 1);
     StageXL.Vector leftDirection = new StageXL.Vector(-1, 0);
     StageXL.Vector rightDirection = new StageXL.Vector(1, 0);
  -  
  -  StageXL.Vector leftUpDirection;
  -  StageXL.Vector rightUpDirection;
  -  
  -  StageXL.Vector leftDownDirection;
  -  StageXL.Vector rightDownDirection;
  -  
  +
  +  StageXL.Vector upLeftDirection;
  +  StageXL.Vector upRightDirection;
  +
  +  StageXL.Vector downLeftDirection;
  +  StageXL.Vector downRightDirection;
  +
     DirectionSystem() {
  -    leftUpDirection = upDirection.rotate(-90 * (math.PI / 180));
  -    rightUpDirection = upDirection.rotate(90 * (math.PI / 180));
  -    
  -    leftDownDirection = downDirection.rotate(90 * (math.PI / 180));
  -    rightDownDirection = downDirection.rotate(-90 * (math.PI / 180));
  +    upLeftDirection = upDirection.rotate(-90 * (math.PI / 180));
  +    upRightDirection = upDirection.rotate(90 * (math.PI / 180));
  +
  +    downLeftDirection = downDirection.rotate(90 * (math.PI / 180));
  +    downRightDirection = downDirection.rotate(-90 * (math.PI / 180));
     }
   
     /**
  
positive.code:    */
    void rotateDirectionsRadians(num radians) {
      mainDirection = mainDirection.rotate(radians);
      upDirection = upDirection.rotate(radians);
      downDirection = downDirection.rotate(radians);
      leftDirection = leftDirection.rotate(radians);
      rightDirection = rightDirection.rotate(radians);
    }
  
    /**
  
negative.code:   void nullMainDirection() {
      if (!mainDirection.isZero) mainDirection = _zeroVector;
    }
  
    /**
     * Set the main direction's x component to zero.
     */
    void nullMainDirectionX() {
      mainDirection *= _zeroOneVector;
    }
  
    /**
     * Set the main direction's y component to zero.
     */
  