static void ai_spec_searchForAnswer(S s) {
  Set<S> cluster = litciset(s);
  cluster = ai_cluster_forward(cluster, "parses to triple");
  //print("Cluster: " + cluster);
  if (empty(cluster)) ret;
  ai_expandCluster(cluster);
  //print("Cluster expanded: " + cluster);
  cluster = ai_cluster_backward(cluster, "answers triple");
  //print("Cluster: " + cluster);
  if (empty(cluster)) ret;
  ai_postTriple_multi(cluster, "answers", s);
}