Chapter 1. Concentration

Concentration is a memory game you can play even without a computer, just with a deck of cards. Shuffle the cards, lay them face down on a table and at each turn choose and flip any two cards with faces up&;.

If they match (both cards are Aces, Twos, Threes, and so on), remove them from the table. If not, lay them face down again and pick another couple of cards. The game is completed when, due to successful matches, all cards have been removed from the table.