/** Show a hint at the position. */
 public void hintAt(MyPoint pos, int hintType) {
   MyPoint centerPosition = pos.clone();
   MyImage[] image = new MyImage[1];
   image[0] = ImageAid.loadFromFile(SourceManagement.HintFile[hintType]).elementAt(0);
   MyPoint[] positions = new MyPoint[20];
   int[] indexMapper = new int[20];
   for (int i = 0; i < 20; ++i) {
     positions[i] = new MyPoint(centerPosition.x, centerPosition.y + dys[i]);
     indexMapper[i] = 0;
   }
   ImageMapper imageMapper = new ImageMapper(image, positions, indexMapper);
   HintEffect effect = new HintEffect(imageMapper, 19);
   effectPainter.addEffect(effect);
 }