static LS stringChunks(S s, int chunkSize) {
  int rows = intRatio_ceil(l(s), chunkSize);
  LS out = emptyList(rows);
  for y to rows:
    out.add(substring(s, y*chunkSize, (y+1)*chunkSize));
  ret out;
}

static LS stringChunks(int chunkSize, S s) {
  ret stringChunks(s, chunkSize);
}