So Easy, you’ll perform this trick one minute after you get it. Two sponge rubber boomerangs apparently change size at will. First the red one is the biggest and then the yellow one. As you tell the story, you explain that when you tell one lie, you usually have to tell another to cover that one . . and then another . . and another and so on . One lie stretches into another. Just like a real boomerang, lies can come back to hurt you.