// TODO: optimize
static bool anyRectsOverlap(L<Rect> l) {
  for (int i = 0; i < l(l); i++) {
    Rect a = l.get(i);
    for (int j = i+1; j < l(l); j++)
      if (rectsOverlap(a, l.get(j)))
        true;
  }
  false;
}