// similarity = e.g. 0.99f
static L<FoundImg> bwRawImageSearchInPart(BWImage big, BWImage pat, Rect part, float similarity, int maxEntries) {
  new L<FoundImg> found;
  int wp = pat.getWidth(), hp = pat.getHeight();
  int w = big.getWidth(), h = big.getHeight();
  float maxError = (1f-similarity)*wp*hp;
  int x2 = min(w-wp, part.x2());
  int y2 = min(h-hp, part.y2());
  for (int y = part.y; y < y2; y++)
    for (int x = part.x; x < x2; x++) {
      float diff = bwImageSectionsSimilarity(big, pat, x, y, maxError);
      if (diff <= maxError) {
        float sim = 1-diff/(wp*hp);
        Rect r = new Rect(x, y, wp, hp);
        found.add(new FoundImg(r, sim));
        ping();
        if (l(found) >= maxEntries) ret found;
        x += wp-1;
      }
    }
  ret found;
}

Began life as a copy of #1005396