Quantum Tic-Tac-Toe

Every move lives in two squares at once.

Starter
About 5 min
No sign-in
One shot: nothing is saved

Your move: tap two squares to put your mark in both.

X moves first. Place one mark in two squares at once.

Setting up the table…

Before you play

In ordinary tic-tac-toe a mark sits in one square. Here a mark is placed in two squares at once, and only one of them will turn out to be real.

Two squares joined by a mark are entangled. When the links close into a loop the position is forced to decide, and the decision spreads through every mark in the loop.

How to play

Tap two squares to place your mark in both. The small number is the turn it was played.
If your marks close a loop, your opponent chooses which square your last mark becomes real in.
Three real marks in a row win. If both players finish a row at once, the row finished by earlier turns wins.

Your challenge

Win a game by closing a loop of your own marks on purpose, so the collapse works for you.

Optional. Nothing is tracked, so the result screen is your scorecard.

Ideas in this game

Superposition
Entanglement
Measurement

Go deeper

Games are free play: no account, no score, no tracking. A free account adds the Academy, where lessons keep a streak and earn badges and certificates, and the Studio for circuits of your own.

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