You show a small wallet with a prediction, which you place face down on the table. You also show a packet of cards with blue backs, telling the spectator that they are the four Kings.
Ask them to name either the red or the black Kings.
Imagine that they select the black Kings. You say that you had predicted in advance that they would select the black Kings and proceed to fan the packet of cards to show that the two black Kings are FACE UP.
The spectator is then asked to name any one of the black Kings.
The King of Clubs is selected and when it is turned over, it has a GREEN back, different from the rest. However, when your prediction is turned over, it has the word GREEN written on it. You then show the other black King to have a YELLOW back.
For the finale, the spectator is probably wondering about the red Kings. Well, when you turn those over, they have the words DIFFERENT COLORS written on them.