// draw faint one times one pixel chess board to indicate how big a pixel is
svoid drawPixelChessboard(BufferedImage image) {
  int w = image.getWidth(), h = image.getHeight();
  for y to h:
    for x to w:
      setPixel(image, x, y, even(x+y) ? Color.lightGray : Color.white);
}

Began life as a copy of #1035000