code: public Rectangle rotate() {
  		Rectangle rect = new Rectangle(lly, llx, ury, urx);
  		rect.rotation = rotation + 90;
  		rect.rotation %= 360;
  		return rect;
  	}
docs: Rotates the rectangle.
  Swaps the values of llx and lly and of urx and ury.
  
  @return the rotated <CODE>Rectangle</CODE>