svoid test_ImageSimilarityAtScale(BufferedImage img1, BufferedImage img2, int featureSize default 1) {
  ImageSimilarityAtScale algo = new(
    IntegralImage(img1), IntegralImage(img2), featureSize);
  algo.verbose = true;
  algo.run();
  while (algo.step()) {
    print("Value: " + algo! + " after " + nBlocks(algo.blocksCalculated()));
  }
}