anchor.diff:  
   %%% Internal Functions
   
  -assertComplexWithin([{ExpRe,ExpIm}], Tolerance, [{ActRe,ActIm}|_]) ->
  -    [ assertComplexWithin(ExpRe, Tolerance, ActRe), assertComplexWithin(ExpIm, Tolerance, ActIm) ];
  -assertComplexWithin(Expected, Tolerance, Actual) ->
  -    io:format("Does ~p = ~p +/- ~p?~n", [Actual,Expected,Tolerance]),
  -    ?_assert(erlang:abs(Expected - Actual) =< Tolerance).
  +assertComplexWithin({ExpRe,ExpIm}, Tolerance, [{ActRe,ActIm}|_]) ->
  +    [
  +     ?_assert(erlang:abs(ExpRe - ActRe) =< Tolerance),
  +     ?_assert(erlang:abs(ExpIm - ActIm) =< Tolerance)
  +    ].
   
   assertWithin(Expected, Tolerance, [Actual|_]) ->
  -    io:format("Does ~p = ~p +/- ~p?~n", [Actual,Expected,Tolerance]),
  -    ?assert(erlang:abs(Expected - Actual) =< Tolerance ).
  +    ?assert(erlang:abs(Expected - Actual) =< Tolerance).
   
   %%% Unit Tests
   
  
positive.code:     lists:map(fun({Input,Expected}) ->
                        assertComplexWithin(Expected, 0.000000001,  execute(Input, []))
                end,
                [ {"5,3", [{5,3}]},
                  {"-2.0e-3,5", [{-0.002,5}]},
                  {"4,-7.0e3", [{4,-7.0e3}]},
                  {"-0.4,-0.75", [{-0.4,-0.75}]} ]).
  
  % Basic Arithmetic
  adds_two_numbers_test_() ->
  
negative.code: raises_a_number_to_a_power_test_() ->
      [
       ?_assertEqual([32.0], execute ("2 5 **",[])),
       assertComplexWithin({-7.461496614688569,2.8854927255134477}, 0.00000001, execute("2 3,4 **",[])),
       assertComplexWithin({-37.999999999999986,41.000000000000014}, 0.00000001, execute("3,4 2.5 **",[])),
       assertComplexWithin({-14.405859669065997,101.33689785344499}, 0.00000001, execute("1,2 3,-2 **",[]))
      ].
  
  changes_the_sign_of_the_top_number_test_() ->
  