public static function ringSector(Point $center, Angle $start, Angle $stop,
			$radius, $innerRadius, $ccw = false)
	{
		$points = new Points($center, false);
		if ($ccw) { $swap = $start; $start = $stop; $stop = $swap; }
		$points->addPoint($center)->translateX($radius)->rotate($center, $start);
		$points->addPoint($center)->translateX($radius)->rotate($center, $stop);
		$points->addPoint($center)->translateX($innerRadius)->rotate($center, $stop);
		$points->addPoint($center)->translateX($innerRadius)->rotate($center, $start);
		return $points;
	}