--- a/rps.erl	Wed Feb 26 01:38:26 2014 +0900
+++ b/rps.erl	Wed Feb 26 01:46:12 2014 +0900
@@ -93,7 +93,7 @@
     receive
         {Object, Who} ->
             ObjectIsOk = lists:any(fun(X) -> X =:= Object end, get_rules()),
-            ChoiceMade = lists:any(fun({_, Player}) -> Player =:= Who end, Choices),
+            ChoiceMade = lists:keymember(Who, 2, Choices),
             case ObjectIsOk andalso not ChoiceMade of
                 true ->
                     room(Players, [{Object, Who}|Choices]);