Two coins are shown in the palm of your left hand: one English penny and one half dollar. You place the English penny in your pocket, yet, when you open your hands, both coins will be in your palm again. Then you place the half dollar coin in your pocket and again the coin returns to your hand. Again you place the half dollar coin in your pocket and again the coin returns to your hand. Finally you place the English penny in your pocket, open your hand and there is no coin. The last coin has disappeared!