static ItIt<Pair<T3S>> ai_allBridgeSextets(S lineA, S lineB, O... _) {
  ret ai_allBridgeSextets(nlTok6(a), nlTok6(b));
}

// optional parameter: plusFull (default false)
static ItIt<Pair<T3S>> ai_allBridgeSextets(LS tokA, LS tokB, O... _) {
  L<IntRange> rangesA = asList(wordIntRangesIterator_shortestFirst(tokA, plusFull := true));
  L<IntRange> rangesB = asList(wordIntRangesIterator_shortestFirst(tokB, plusFull := true));
  ret combineZigZag(rangesA, rangesB);
}