def to_s
      s = ""
      s << width.to_i.to_s if width > 0
      s << "x#{height.to_i}" if height > 0
      s << modifier.to_s
      s
    end
def to_s
      s = ""
      s << width.to_i.to_s if width > 0
      s << "x#{height.to_i}" if height > 0
      s << modifier.to_s
      s
    end
Returns the width and height in a format suitable to be passed to Geometry.parse