static <A> LL<A> listToChunks(L<A> l, int chunkSize) {
  int rows = intRatio_ceil(l(l), chunkSize);
  LL<A> out = emptyList(rows);
  for y to rows:
    out.add(subList(l, y*chunkSize, (y+1)*chunkSize));
  ret out;
}

static <A> LL<A> listToChunks(int chunkSize, L<A> l) {
  ret listToChunks(l, chunkSize);
}