Quadgrid: 3D Tic Tac Toe XO

Tic tac toe stopped being a challenge when you were seven. Quadgrid makes it one again.

Quadgrid is tic tac toe on a 4x4x4 cube: four floors of sixteen squares, stacked one above the other. Get four in a row and you win, and a row can run any way you like. Across a floor. Straight up through all four floors. Corner to corner, right through the middle of the cube. That makes 76 ways to win, and most of them are hiding where your eyes don't look yet.

So the game changes. You stop just blocking and start building. You learn to spot the line climbing from the bottom floor to the top, to set up two threats at once so your opponent can only stop one, to see the win that is three moves away. Spin the cube with a finger, pull the floors apart to look inside, and play it however you see it best.

Play someone real. Find an opponent online, or send a friend a link and play on your own phones. Take your time in a turn-based game, with up to three days for each move and a notification when it's your turn. Or play Blitz: three minutes each, two seconds added every move, and no time for second thoughts.

Or climb the ladder. Four computer opponents are waiting, from Pip, who is still learning the cube, to The Architect, who plans winning attacks four moves deep and only opens up once you've beaten Vega. Win as X, win as O and win with hints off to earn all three stars from each. Beat Vega and the Chess theme is yours too.

A new puzzle every day. Each one is a position from a real game with one question: can you find the win? Some take one move, the hardest take four, and you get three hearts to solve it. Out of hearts? Watch the winning line play out, move by move. Keep your streak going and share your result without giving the answer away.

New to the cube? Five short lessons show you the lines everyone misses and the double threat that wins games. Two people, one phone? Pass and Play is right there. No signal? Everything except online play works offline.

There's no account and nothing to sign up for. Open it and play.

Quadgrid is free, with a small banner ad on some screens. A one-time purchase removes the ads.