static ItIt<IF1<BufferedImage, L<Rect>>> chessOCR_colorBasedMetaSegmenter(BufferedImage img, ParameterizedSegmenter baseSegmenter) {
  MultiSet<S> histogram = histogram332(img);
  ret mapI(histogram.highestFirst(),
    color -> {
      ParameterizedSegmenter seg = shallowNonTransientClone(baseSegmenter);
      seg.distanceFromColor(color332toRGB(color));
      ret seg;
    });
}