anchor.diff:      ClauseList1=filter_equimatchable_clauses(ClauseList),
       ReteTotal=
           lists:foldl(
  -          fun(Clause, Rete) ->
  +          fun(#clause{args=[#var{}|_]}, Rete) ->
  +                  Rete;
  +             (Clause, Rete) ->
                     merge(clause_to_rete(Clause), Rete)
             end, #rete{}, ClauseList1),
       {make_alpha_layer(ReteTotal), make_beta_layer(ReteTotal), ReteTotal}.
  
positive.code: 
  -spec merge(#rete{}, #rete{}) -> #rete{} .
  
  merge(#rete{}=Path,
        #rete{bnodes=[],anodes=[]}=Tree) ->
      merge(Path,Tree#rete{bnodes=[make_terminal_bnode()]});
  
negative.code:                     {#rete{anodes=[], bnodes=[make_terminal_bnode()]},[]}, 
                      AlphaFormsOredred),
      #rete{anodes=lists:reverse(ANodeList),
            bnodes=lists:reverse([H#bnode{pnodes=true}|T])};
  clause_to_rete(#clause{args=[#var{}|_]}) ->
      #rete{}.
  
  %
  % Merge left to right
  