1. First, 21 picture cards are shown on the screen, and one of them is remembered by the player.
2. Display seven cards on the screen and ask if there is one card you remembered, and choose which group your card belongs to.
3. Repeat the above process three times and the computer finds your card.
* Don't look at your card long because your smartphone can detect your eyes
upgrade : It takes long to load one of the picture cards