On the episode of Seinfeld where the whole gang is going to a party (I think a Christmas party), Kramer and George go to the liquor store to get some wine for the party. They first dropped Elaine and Jerry off at the bakery. They wanted to get a bobca. Anyway, while they are there, Jerry gets a black and white cookie. Through the course of their conversation, the camera switches back and forth and the black and white sides of the cookie change. The bite taken out of it is always facing up, so you know that he didn't just turn it over. Take a look, it's pretty funny.