anchor.diff:  %% The command frequencies are deliberately manipulated to make it more
   %% likely that compares will take place once both trees are updated.
   %%
  -
  -
  -%% Notes/Questions for JDM
  -%% There's much knowledge in here about how *_index_hashtrees work, which makes
  -%% me worried that hashtree itself isn't factored correctly. Example: why would it be
  -%% different if memory levels are used or not? Why _should_ hashtree allow it to be?
   
   
   -module(hashtree_eqc).
  
positive.code: start(Params, [TreeId | ExtraIds], Tree1OpenOrEmpty, Tree2OpenOrEmpty) ->
      {Segments, Width, MemLevels} = Params,
      %% Return now so we can store symbolic value in procdict in next_state call
      T1A = create_and_open_hashtree(TreeId, Segments, Width, MemLevels, Tree1OpenOrEmpty, ExtraIds),
  
      put(t1, T1A),
  
      %% TODO: Can we just use Segments, Width, Memlevels?
      T2A = create_and_open_hashtree(TreeId, hashtree:segments(T1A), hashtree:width(T1A), 
          hashtree:mem_levels(T1A), Tree2OpenOrEmpty, ExtraIds),
  
      put(t2, T2A),
  
  
negative.code: next_state(S,_R,{call, _, local_compare1, []}) ->
      S.
  
  
  %% Property to generate a series of commands against the
  %% hashtrees and afterwards force them to a comparable state.
  