Mad Numbers

You and your opponent take turns. The first player can choose from any box in a horizontal line. All the boxes in a vertical line from that box can then be chosen by the second player, and so on. The lighter boxes will add points to your final score, while the darker ones will subtract them. Choose the boxes in a way that will add points to your score, while making it harder for your opponent to gain points. The player with the most points at the end of the game wins.