sS test_G22RegionThinner_fullThinning(S imgString) {
  var img = bwImageFromString(imgString);
  var image = toBufferedImage(img);
  var itr = Gazelle22_ImageToRegions(
    new FunctionTimings, image, new SnPSettings(image, 2));
  itr.withDiagonals(true);
  var region = g22_darkestRegion(itr!);
  
  G22RegionThinner_v2 thinner = new(region);
  stepAll(thinner);
  ret bwImageToString(regionToBWImage_fullImageSize(thinner!));
}

Began life as a copy of #1034981