I can read minds, do you believe it?

Do you believe that I can read minds? Let's play a game together.

You see, there are 9 cards on the screen. You can select a card at random, point your finger at it, and then move your finger horizontally or vertically. For example, you first point your finger at the Ace of Spades, then move one step to the right, your finger points to the 2 of Hearts, and then move one step down, your finger points to the 5 of Spades. Be careful not to move diagonally.

Do you understand the rules? Now, the mind reading officially begins.

First, please select a black card, note that it must be black. Then, point your finger at it!

Then, please follow the rules just now and take 5 steps horizontally or vertically at will.

1, 2, 3, 4, 5

Okay, keep your fingers still. I believe that your fingers are not on the Ace of Spades. So I take the Ace away. Note: After taking it away, the Ace cannot be moved.

Next, please continue to move your finger, starting from where you just stopped, and take 4 more steps at random.

1, 2, 3, 4

All right, keep your fingers. Your fingers must not be pointing to the 3 of clubs and the 7 of clubs, I'll take them away too.

Please move your finger 3 more times. Again, the same thing: the position of the card that has been taken away cannot be moved again.

1, 2, 3

Okay. Your finger must not be on the 2 of Hearts, so I'll take that away too.

There are now 5 cards left, please move your finger 2 more steps.

1, 2

I guess your fingers are not on the 4 and 6 of hearts, so I remove them as well. Now there are only 3 cards left, and your fingers must be on one of them.

Finally, please move your finger 1 more step.

OK! Don't move your fingers. Your fingers must not be on the 5 of spades and the 9 of spades. You must be pointing at the 8 of diamonds!

Did I guess right?

Do you know how mind reading works? It's actually very simple.

Switching back to the original cards, you will find that the red cards and the black cards are placed alternately. If you move 1 step, the color of the card will definitely switch, that is, red becomes black, or black becomes red; if you move 2 steps, the color will definitely switch back.

In other words: when the number of steps is odd, the color of the card it points to will change, and when the number of steps is even, the color of the card remains unchanged.

At the beginning, I asked you to choose a black card, and then move 5 steps. I am sure that you must be pointing to a red card now, so I can take away the Ace of Spades. Then I asked you to move 4 steps. I am sure that you must still be pointing to a red card, so I took away the 3 of Clubs and the 7 of Clubs. Finally, according to my rules, no matter which black card you choose at first, and no matter how you move, you can only get one card in the end, that is the 8 of Diamonds. Do you understand?

Go try it out with your friends!

Source: Mr. Li Yongle