Array Game

Hello everybody!

In this game, you have been given a random array with 10 pairs of characters in total. Once you are ready, all characters will disappear and transform into a hidden one, so memorize the positions of every character. Every player can make a mistake only 4 times, on the 4th time the game will stop. If the player manages to find all the right positions, the game stops and he wins.
If you have any suggestion to improve the code or the functionality of the game, don't be afraid to let me know. I will happily read your comments!