anchor.diff:      Root;
   
   insert_bulk([Leaf | Rest], Root, Params) ->
  -    insert_bulk(Rest, maybe_reroot(insert_leaf(Leaf, Root, Params)), Params).
  -
  -insert_leaf(Leaf, Node0, Params) ->
  +    insert_bulk(Rest, maybe_reroot(insert_leaf(Leaf, Root, 1, Params), Params), Params).
  +
  +insert_leaf(Leaf, Node0, Level, Params) ->
       case has_leaves(Node0) of
           true ->
  -            insert_child(Leaf, Node0, Params);
  +            insert_child(Leaf, Node0, Level, Params);
           _False ->
               {SubNode0, Node} = pick_subnode(bound(Leaf), Node0, Params),
  -            SubNode = insert_leaf(Leaf, SubNode0, Params),
  -            insert_child(SubNode, Node, Params)
  +            SubNode = insert_leaf(Leaf, SubNode0, Level + 1, Params),
  +            insert_child(SubNode, Node, Level, Params)
       end.
   
   pick_subnode(Against, {_, Bound, Children}, Params) ->
  
positive.code: 
  %%
  
  maybe_reroot(Roots) when is_list(Roots) ->
      newnode(Roots);
  
  maybe_reroot(Root) ->
      Root.
  
  update_root(RStar, Root) ->
      setelement(3, RStar, maybe_reroot(Root)).
  
  %%
  
  
negative.code:     is_integer(MinCap), MinCap > 1,
      is_integer(MaxCap), MaxCap >= 2 * MinCap,
      is_integer(ChooseCutout), ChooseCutout > 0,
      is_integer(ReinsertCount), ReinsertCount >= 0, ReinsertCount < MaxCap ->
      {?MODULE, {MinCap, MaxCap, ChooseCutout, ReinsertCount}, newnode()}.
  
  %%
  