anchor.diff:                      %% Increment it.
                       {ok, _} = lasp:update(Ad, increment, Id),
   
  -                    client(Id, AdsWithContracts, AdList0)
  +                    client(Runner, Id, AdsWithContracts, AdList0)
               end
       end.
   
   %% @doc Simulate clients viewing advertisements.
  -simulate(ClientList) ->
  +simulate(_Runner, ClientList) ->
       %% Start the simulation.
       Viewer = fun(_) ->
               Random = random:uniform(length(ClientList)),
  
positive.code: 
      %% Generate Rovio's advertisements.
      {ok, RovioAds} = lasp:declare(?SET),
      lists:map(fun(Id) ->
                  %% Generate a G-Counter.
                  {ok, CounterId} = lasp:declare(?COUNTER),
  
                  %% Add it to the advertisement set.
                  {ok, _} = lasp:update(RovioAds,
                                        {add, #ad{id=Id, counter=CounterId}},
                                        undefined)
  
                  end, RovioAdIds),
  
      %% Generate Trifork's advertisements.
      {ok, TriforkAds} = lasp:declare(?SET),
      lists:map(fun(Id) ->
                  %% Generate a G-Counter.
                  {ok, CounterId} = lasp:declare(?COUNTER),
  
                  %% Add it to the advertisement set.
                  {ok, _} = lasp:update(TriforkAds,
                                        {add, #ad{id=Id, counter=CounterId}},
                                        undefined)
  
                  end, TriforkAdIds),
  
      %% Union ads.
      {ok, Ads} = lasp:declare(?SET),
  
negative.code:                 0 ->
                      %% No advertisements left to display; ignore
                      %% message.
                      client(Runner, Id, AdsWithContracts, AdList0);
                  _ ->
                      %% Select a random advertisement from the list of
                      %% active advertisements.
  