## Whoa…I never thought of it that way.

Here’s a little mathematical game you can play with cards, which has a trick up its sleeve that you would not anticipate.  The game only requires the cards 1 through 9, and the way the game works is that two players take turns alternating to pick up a card, and the first person to have three cards (any three cards, and you can have more than three cards in your hand) that add up to 15 wins.  So if I have 1, 3, 6, and 8, I win because 1, 6 and 8 add up to 15.  Use the ace to substitute as the one card.  The game itself is called Pick15, and requires in depth analysis of the possibilities to make 15 and insight into what the other player is going to play.  Try it out, it’s a very interesting game, and has quite a lot of strategy.  Here’s one example game: I take 5, he takes 3, I take 4, he takes 6, I take 9, he takes 2, I take 6.  I win because I have 4, 5, 6.  The game itself feels like it has some really basic intuition to it, yet at the same time feels quite complex.  So let’s add a dash of perspective.  Ever heard of a magic square?

Now think of the game that just happened, and think of it as taking boxes in this square.  Each row, column and diagonal in the 3×3 magic square adds up to 15, and so in its essence you are trying to complete one of these.  Sound familiar?  You bet, its tic tac toe.  Whaaaaa…