XX     X             XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX
XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX     XX
_____XX_____X_____________XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XXXX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____XX_____X