The challenge for the gray cells? Why not! Use your head to reposition all the cubes on the Mahjong board as it should be. Is this time you manage to clear the board before your opponent, and by the way collect more cash? Do your best and show that you can make a fortune through your clever mind! It's sometimes enliven gray cells, and even give them a hard time. Think if you has play with buddy for real money - one of you would be very rich! Let this thought motivate you during the implementation challenges for the brightest!