Very google trick but instead of using a red queen of club to match the blue one, I suggest to use
a red blank card on wich I have written « Queen of club ».
By dooing that way you may prepare
some other cards and execute the same trick an another day to the same persons and have a
different result for the matching cards as wells as (if you are lucky) for the number of cards
(except for the nine red ones).
Good luck and best regards from France.