In the episode "For All You Spies."

Philip and Sophie are playing chess. Sophie goes to bed. Emma comes in late at the beginning of the episode and acts like she is a spy. She says she's stealthy and then she knocks over the chess board and says she failed that part of the training.

When she has the TWO BLACK KNIGHTS she says "Night Night" while passing the chess pieces. but when they are in Philip's hand he has ONE BLACK & ONE WHITE

Now that is magic!