# Girl Plays Tic-Tac-Toe Game with Mail Carrier to Beat COVID-19 Blues

paper board game attached to mailbox begins a daily game

## A hand-drawn tic-tac-toe board is helping one girl connect with her mail carrier, USA Today reported. The board is taped to her mailbox and she plays against her unseen opponent at the rate of one turn per day. Simple games help cure boredom.

According to USA Today, the Ohio girl is using the popular child’s game as a way of beating the monotony of being stuck at home. “This is one way that the Britton Elementary fifth-grader has escaped the boredom of the coronavirus stay-at-home order and pandemic,” the article said. “She also learned to fry churros and made cards and signs for all the neighbors. Julia put her first board in the mailbox on April 30—with a key at the bottom that read ‘O=You X=Me”—and left [a pen] inside. And then she waited.”

USA Today also spoke with the girl’s mail carrier, who said at first she was reluctant to get involved but had since changed her mind, and now it brightens her day. Tic-tac-toe is just one of many simple at-home games that can help sharpen your brain and cure at-home boredom.

#### Three in a Row, or Not

There’s one tip to increase your odds at winning tic-tac-toe. Everyone knows the player who goes first has the advantage, but where should that first “X” go?

“As a practical matter, X should start in one of the four corners, since O has only one safe response, which is to play in the middle,” said Dr. Arthur T. Benjamin, Professor of Mathematics at Harvey Mudd College. “If O doesn’t play in the middle, X can force a win.”

However, if you think that ordinary tic-tac-toe is getting a bit boring, Dr. Benjamin suggested trying an interesting variation on the game—one that inverts it.

“Suppose we change the rules so that if someone gets three in a row, instead of becoming the winner, they lose instead,” he said. “Now how does that change the game? It becomes much more interesting, right? This time, since X goes first and has to make five of the nine moves, X is at a disadvantage.”

#### Getting to 21, No Cards Required

Another clever game you can play doesn’t require a game board. In fact, it doesn’t require anything at all, other than brainpower. Dr. Benjamin calls it The Game of 21, but it isn’t Blackjack.

“Here’s how it goes—I pick a number between one and three; you, then, add a number between one and three to create a new total,” he said. “I add another number from one to three to that total, and we continue like this until the total reaches 21. Whoever gets to 21 is the winner.”

Dr. Benjamin offered a sample game to help explain it. He said if he starts with three, then his opponent adds two, he’ll add another three to make eight. The opponent adds one, then Dr. Benjamin adds one, and they reach 10. Two more from the opponent makes 12, he adds one to reach 13, and the opponent adds three to make 16. If Dr. Benjamin adds one more, he has 17. Then his opponent adds one more to arrive at 18 and Dr. Benjamin adds three and lands on 21.

“To make the game fair, you should take turns going first,” he said.

If you’re bored at home during quarantine or if you have kids you want to keep entertained, some simple games like the inverted tic-tac-toe or The Game of 21 can break up some of that monotony.

Dr. Arthur T. Benjamin contributed to this article. Dr. Benjamin is Professor of Mathematics at Harvey Mudd College. He earned a Ph.D. in Mathematical Sciences from Johns Hopkins University in 1989.