Several plastic cards with pictures of birds are shown. Each card has a different number of birds on the front and a different number of birds on the back. While your back is turned, a spectator arranges the pictures of birds in any way they wish. As soon as you turn around, you can instantly and accurately state the number of birds showing. Repeat it if you wish. Once again you turn your back. They mix the cards, some front and some back. Then, they put the cards into a tightly sealed plastic case. Still, when you turn around, you can instantly state the total number of birds showing.