static Pt brightestPixel(BWImage img) {
  int w = img.getWidth(), h = img.getHeight();
  new LPair<Pt, Int> l;
  int bestX = -1, bestY = -1, score = -1;
  for y to h:
    for x to w: {
      int val = img.getInt(x, y);
      if (val > score) {
        bestX = x;
        bestY = y;
        score = val;
      }
    }
      
  ret score >= 0 ? Pt(bestX, bestY) : null;
}