**Tic-tac-toe**, also called **noughts and crosses** or **Xs and Os** is a game for two people that only requires pencil and paper, although you can also use a board with tokens.

The **board** – which can be a drawing on a paper or other place – consists of a square that is crossed by two vertical and two horizontal lines, so in total there are three small squares left in the top line, another 3 in the center line and 3 more in the bottom line.

Each player takes turns drawing a cross or a circle in a square – or placing tokens of different shapes or colors. The winner is the one who manages to place three equal pieces in a row, either vertically, horizontally or diagonally.

Games played on **three-in-a-row boards** can be traced back to **ancient Egypt**, where such game boards have been found on roofing tiles dating from around 1300 BC.

An **early variation of tic-tac-toe** was played in the **Roman Empire**, around the 1st century BC. It was called terni lapilli (three pebbles at a time) and instead of having any number of pieces, each player had only three – thus, they had to move them around to empty spaces to keep playing. The game’s grid markings have been found chalked all over Rome. Another closely related ancient game is three men’s morris which is also played on a simple grid and requires three pieces in a row to finish, and Picaria, a game of the Puebloans.

**How the game progressed beyond that is a bit more unclear**. Some say there are records of it being played in the Middle Ages, with a mystic attachment to it, but the most concrete reappearance we have of it comes sometime later.

In the **mid-1800s, Britain** used the name noughts and crosses, with nought referring to the O’s (or zeros) used in the game. The **phrase tick-tack-toe** wasn’t used until the **late 1800s**, and there’s some findings that report it might have been used to describe a completely different game.

The **United States** officially adopted the **name tic tac toe** in the **20th century**. Historians aren’t completely clear about the origin of the game’s name, but it could be referring to the noise of repetitive ticking or writing that goes along with the game’s play.

In **1952, OXO** (or Noughts and Crosses), developed by British computer scientist Sandy Douglas for the EDSAC computer at the University of Cambridge, became one of the first known video games and the first strategy game on a computer. The computer player could play perfect games of tic-tac-toe against a human opponent.

In **1975**, tic-tac-toe was also used by **MIT students** to demonstrate the computational power of Tinkertoy elements. The Tinkertoy computer, made out of (almost) only Tinkertoys, is able to play tic-tac-toe perfectly. It is currently on display at the Museum of Science, Boston.

**Mathematicians** **were intrigued by the game**. Its simple rules and small grid can illustrate mathematical principles like probability. Combinatorics show that there are 362,800 distinct ways to place Xs and Os on the grid, but only 255,168 of them are possible winning combinations. Moreover, after eliminating symmetrical combinations, there are merely 138 distinct winning arrangements. Tic-Tac-Toe becomes a straightforward game to play with these few winning combinations. This also means that players will often find themselves in draws.

Tic-tac-toe is **one of the first games to be played by children **due to its fast setup and easy engagement.

Because of its simplistic format and potential for a game of almost any size, there are many **possibilities for tic tac toe variations**. A common one is **Connect 4**, where a player must create four in a row of their team’s color on an interactive grid board using chips. Other popular examples of tic tac toe variations include **Mojo, Toss Across, Nine Men’s Morris, Quarto, **and** Gobblet**, among many others.

**George Cooper** wrote the words and **John Rogers Thomas** wrote the music for a **song “Tit, Tac, Toe”** in 1876.

On **Hollywood Squares**, nine celebrities filled the cells of the tic-tac-toe grid – players put symbols on the board by correctly agreeing or disagreeing with a celebrity’s answer to a question.

**Tic-Tac-Dough** is an American television game show based on the paper-and-pencil game of tic-tac-toe. Contestants answer questions in various categories to put up their respective symbol, X or O, on the board. Three versions were produced: the initial 1956–59 run on NBC, a 1978–86 run initially on CBS and then in syndication, and a syndicated run in 1990. The show was produced by Barry & Enright Productions.