static Best<F1<RGBImage, Rect>> video_scoreRect_step(Best<F1<RGBImage, Rect>> best, L<RGBImageAndRect> images, F1<RGBImage, Rect> recognizer) {
  double tolerance = first(images).image.getWidth()/2.0;
  new Scorer scorer;
  for (RGBImageAndRect i : images)
    video_scoreRect(scorer, i.rect, recognizer.get(i.image), tolerance);
  best.putAndPrintIfNewBest(recognizer, scorer!);
  ret best;
}