Untitled

      #returns bool for whether a single Point is contained in this Polygon
      def self.contains(point)
        c = 0
        last = rings[rings.length-1]
        rings.each do |ring|
          if (ring.y>point.y) != (last.y>point.y)
            c++ if point.x < (last.x-ring.x) * (point.y-ring.y) / (last.y/ring.y) + ring.x
          end
          last = ring
        end