class App {

  /**
   * Program main entry point.
   *
   * @param args runtime arguments
   */
  public static void main(String[] args) {
    final var scene = new Scene();
    var drawPixels1 = List.of(
        new MutablePair<>(1, 1),
        new MutablePair<>(5, 6),
        new MutablePair<>(3, 2)
    );
    scene.draw(drawPixels1);
    var buffer1 = scene.getBuffer();
    printBlackPixelCoordinate(buffer1);

    var drawPixels2 = List.of(
        new MutablePair<>(3, 7),
        new MutablePair<>(6, 1)
    );
    scene.draw(drawPixels2);
    var buffer2 = scene.getBuffer();
    printBlackPixelCoordinate(buffer2);
  }

  private static void printBlackPixelCoordinate(Buffer buffer) {<FILL_FUNCTION_BODY>}
}

    StringBuilder log = new StringBuilder("Black Pixels: ");
    var pixels = buffer.getPixels();
    for (var i = 0; i < pixels.length; ++i) {
      if (pixels[i] == Pixel.BLACK) {
        var y = i / FrameBuffer.WIDTH;
        var x = i % FrameBuffer.WIDTH;
        log.append(" (").append(x).append(", ").append(y).append(")");
      }
    }
    LOGGER.info(log.toString());
  
<no_super_class>