anchor.diff:                  0 ->
                       %% No advertisements left to display; ignore
                       %% message.
  -                    client(Id, AdsWithContracts, AdList0);
  +                    client(Runner, Id, AdsWithContracts, AdList0);
                   _ ->
                       %% Select a random advertisement from the list of
                       %% active advertisements.
  
positive.code:     io:format("----------------------------------------"),
  
      ok.
  
negative.code:                     %% Increment it.
                      {ok, _} = lasp:update(Ad, increment, Id),
  
                      client(Runner, Id, AdsWithContracts, AdList0)
              end
      end.
  
  %% @doc Simulate clients viewing advertisements.
  simulate(_Runner, ClientList) ->
      %% Start the simulation.
      Viewer = fun(_) ->
              Random = random:uniform(length(ClientList)),
  