1. Please flip in the order of 1, 2, 3, 4, 5, 6, 7, 8, 9, ...
2. Before starting the game, you can first open the cards to view.
3. You can set the length of the view time to increase the challenge.
4. One of MatchMates games.
5. More easier to play.
The idea comes from research :
https://www.youtube.com/watch?v=cPiDHXtM0VA