40 Fun Facts About Tic-Tac-Toe

Which animal was trained to play tic-tac-toe against people in arcade machines popular in the 1970s?

A chicken took its cue from a light the human opponent could not see. A computer chose every move, and the bird had been conditioned to peck wherever the light told it to.

Which 1980s film has a military computer learn that nuclear conflict is futile by playing itself at tic-tac-toe?

WarGames has its computer, WOPR, race through game after game before it abandons the missile launch it was planning and suggests a game of chess instead.

Donald Michie's 1961 machine MENACE learned noughts and crosses using coloured beads kept in 304 of what?

Matchboxes stood in for a computer Michie did not have. Beads were taken out after a defeat and added after a victory, so the machine gradually stopped repeating its bad moves.

MIT students built a computer that plays perfect tic-tac-toe, now a museum piece, from which construction toy?

Tinkertoy rods and spools made up almost the whole machine, built in the 1970s to show what such simple parts could compute. It is now kept at the Computer History Museum in California.

Some of the oldest claimed tic-tac-toe-style boards are cut into the roof slabs of a temple in which country?

Egypt's temple at Kurna carries the boards, long dated to about 1400 BC. That date is disputed, because some of the carvings include Coptic crosses from a far later age.

Which American game show, first aired in the 1960s, seats nine celebrities inside a giant tic-tac-toe grid?

Hollywood Squares used the game mostly as a frame for comedy: its writers supplied the stars with joke answers to deliver before they gave their real replies.

With perfect play from both sides, who wins a standard game of tic-tac-toe?

Neither of them can win if both avoid mistakes, which is why the game is mostly enjoyed by young children who have not yet worked out the best replies.

In noughts and crosses, the British name for tic-tac-toe, a nought is another word for which number?

Zero is called nought in British English, so the name simply describes the two marks on the grid: the noughts are the Os and the crosses are the Xs.

What nickname do American players often give a round of tic-tac-toe that fills the grid with no winner?

Cat's game is the usual American term. Allowing for rotations and reflections, a finished grid can look 138 different ways, and only 3 of them are ties.

Which Milton Bradley game stands a tic-tac-toe-style grid upright so that coloured tokens drop down the columns?

Connect Four went on sale in February 1974. Unlike its pencil-and-paper cousin, it rewards going first: with best play, the opening player can always win.

In the toy game Toss Across, players flip tic-tac-toe targets from blank to X or O by throwing what?

Beanbags strike three-sided blocks that spin on a frame, so luck plays its part: even a perfect throw can leave a block showing the other side's letter.

Tick-tack, a name some dictionaries link to tic-tac-toe, was an old variety of which board game?

Backgammon in an old form went by the name tick-tack, recorded since the 16th century and thought to echo the click of the pieces on the board.

The name tick-tack-toe was also used for a children's slate game of bringing a pencil down on numbers in what way?

With eyes shut, a child stabbed at a slate of numbers and scored whichever one the pencil touched. Some dictionaries trace the modern game's name to this older pastime.

What chess-style term describes a tic-tac-toe move that creates two ways to win at once?

A fork leaves the other side able to block only one of the two threats, so careful defence in tic-tac-toe comes down to stopping these before they form.

If X opens a game of tic-tac-toe in a corner, which reply must O make to avoid a forced defeat?

The center is O's only safe reply. Any other answer to a corner opening lets X set up a double threat and force a win.

Bertie the Brain, a 13-foot machine that played tic-tac-toe with fairgoers in 1950, was built in which Canadian city?

Toronto engineer Josef Kates built it for the Canadian National Exhibition, where visitors queued to play for two weeks before it was dismantled and largely forgotten.

OXO, a 1952 noughts-and-crosses program counted among the first video games, ran on which university's EDSAC computer?

Cambridge doctoral student Sandy Douglas wrote it for a thesis on how people interact with computers, and it could be played only in the laboratory, by special permission.

Tic-tac-toe is a classic classroom example for teaching game-tree search in which branch of computer science?

Artificial intelligence courses use it because the whole game is small enough to map: a program has only 765 essentially different positions to search.

Which long-running game show features Secret X, a contest played on a tic-tac-toe board with no Os?

The Price Is Right gives each contestant one free X and the chance to earn two more by pricing small prizes. The aim is to line them up with an X hidden in the middle column.

Players of OXO, the 1952 computer version of noughts and crosses, entered each move using what device?

A telephone dial picked one of the nine spaces, and the reply appeared on a small cathode-ray screen that the computer normally used to show the state of its memory.

Which comedian was photographed for Life magazine beating Bertie the Brain, a tic-tac-toe machine, in 1950?

Danny Kaye needed several attempts. The machine's builder often stood beside it to turn the difficulty up or down, and at the top setting it was designed to be unbeatable.

Donald Michie, builder of the noughts-and-crosses machine MENACE, spent World War II at which secret British site?

Bletchley Park put him to work on Tunny, a German teleprinter cipher. He later became one of Britain's leading researchers into machines that learn.

Which Japanese-named game stretches the tic-tac-toe idea to five in a row, traditionally using black and white stones?

Gomoku takes its name from the Japanese for five pieces. Because stones are never moved once placed, it can be played with pencil and paper as well.

Which American company sold a multi-level 3D tic-tac-toe set under the name Qubic?

Parker Brothers stacked plastic boards into a 4×4×4 cube, and its rules said that up to three people could play at once.

Number Scrabble is tic-tac-toe in disguise, as becomes clear when its numbers are laid out on which mathematical grid?

A magic square of the numbers 1 to 9 has every line adding up to 15, so picking three numbers that total 15 is exactly the same as claiming three cells in a row.

Quantum tic-tac-toe lets one mark sit in two spaces at once to illustrate which idea from physics?

Superposition is the heart of the variant, which its inventor Allan Goff describes as a way to introduce quantum physics without any mathematics.

In Notakto, a tic-tac-toe variant where both players mark only Xs, what happens to whoever completes the last line?

They lose, because the whole aim is to avoid finishing a row. The idea is said to have come from a five-year-old who suggested a game in which both sides played X.

In ultimate tic-tac-toe, played on nine small boards at once, what decides which board a player must use next?

The previous move does: whichever cell a mark lands in within its small board points to the matching board for the next turn, so a sly move can send a rival somewhere useless.

Which author borrowed a British name for tic-tac-toe for Noughts & Crosses, novels set in a segregated Britain?

Malorie Blackman turns history around in the books: the dark-skinned Crosses hold power over the lighter-skinned Noughts, and the story follows a friendship across that divide.

In three men's morris, an ancient relative of tic-tac-toe, what is a winning row of three pieces called?

A mill is made by sliding pieces as well as placing them: each side has only three, so once all are down they move from point to point until somebody lines them up.

Boards for nine holes, a medieval relative of tic-tac-toe, were carved into seats at which kind of English building?

Cathedrals including Canterbury, Salisbury and Norwich had the boards cut into their cloister seats, a sign of how popular the game was in 13th-century England.

Which Latin poet described a three-in-a-row board game in Ars Amatoria, his verse guide to love?

Ovid advised women to learn the game, in which each side has three pieces and wins by lining them up, on the grounds that love often begins during play.

The ancient three-in-a-row game three men's morris is known as tapatan in which Asian country?

Philippines players know it as tapatan and use the board with diagonal lines, on which each side places three pieces and then slides them in search of a row.

In Hungary, a five-in-a-row pencil game related to tic-tac-toe is named after which single-celled organism?

Amoeba comes from the winner's reward: fencing in the finished game with a tight line around the marks, which leaves a blob shaped like the creature.

In the variant known as wild tic-tac-toe, what is each player free to place on every turn?

Either X or O may go down, so no mark belongs to anyone. The freedom tips the balance: whoever moves first can always win.

What term do theorists use for a pastime such as tic-tac-toe, whose result under perfect play is fully known?

Solved does not have to mean simple: checkers only joined the list in 2007, when Jonathan Schaeffer's team finished working through it by computer.

Which mathematician devised the strategy-stealing argument, showing tic-tac-toe's second player can never force a win?

John Nash came up with it in the 1940s for the board game Hex, and the same reasoning covers any contest in which an extra move can never hurt the side that makes it.

The Latin name terni lapilli, given to an ancient forerunner of tic-tac-toe, refers to three of which objects?

Pebbles were all the equipment needed. The name means three pebbles at a time, because each side had only three pieces and had to keep moving them to stay in the contest.

Gary Gabrel invented Pente, a five-in-a-row cousin of tic-tac-toe, while washing dishes at what kind of restaurant?

A pizza parlor in Stillwater, Oklahoma, employed him while he was at college, and he later planned to give up his manager's job there to sell the game full time.

Bertie the Brain, a 1950 tic-tac-toe machine, was built to show off a miniature version of which electronic part?

The vacuum tube in question was Josef Kates's tiny additron, but patent problems kept it out of other computers until newer components had made it obsolete.