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