docs: public static void writeImageToPpm(int[][] image, String ppmFileName) throws IOException {
          try (BufferedWriter ppmOut = new BufferedWriter(new FileWriter(ppmFileName))) {
              int rows = image.length;
              int cols = image[0].length;
              ppmOut.write("P3\n");
              ppmOut.write("" + rows + " " + cols + " 255\n");
              for (int[] anImage : image) {
                  StringBuilder s = new StringBuilder();
                  for (int j = 0; j < cols; j++) {
                      s.append(anImage[j] + " " + anImage[j] + " " + anImage[j] + "  ");
                  }
                  ppmOut.write(s.toString());
              }
          }
  
      }