Remember your childhood classes when you got bored and started scribbling things on the back of the notebook? One of the mot popular things on the backs of notebooks used to be the game tic-tac-toe. The simple but interesting game kept children engrossed as they waited for the bell to ring. 

But with only 9 squares involved, there weren't many permutations that you could do. And people soon started finding tricks that would lead to every game ending in a tie. Eventually, it became a bit boring. 

Source: Imgur

And then, mathematicians decided to get involved. Trust them to step things up. As an anonymous user on Quora discovered, some mathematicians on a picnic created a different variant of the popular game. Instead of playing on the usual board, they created a 3x3 grid of 3x3 boards. This is what it looks like. 

Source: Quora

Yes, this is a single board. Not 9 different games. Now, let us come to the rules of the game. 

You start by marking small squares attempting to win individual boards.  

Source: Quora

And winning boards is exactly like winning them on the regular version of the game. You take three squares in a row, and the board is yours.

And if you win three consecutive boards, you win the game. If one of the boards is tied, that counts for neither X nor O.  

Source: Quora

Right now, it sounds just like an extrapolated version of the old game. But let now come to the most interesting rule of the game.

You don't get to pick which board you play on. That is determined by your opponent's previous move. And your move determines which board your opponent will play on next.

For example, if you play here

Source: Quora

Your opponent must play on the corresponding board on the grid i.e. the rightmost board in the top row.

Source: Quora

And what happens if your opponent sends you to a board that has already been won/tied? In that case, you're free to make a move anywhere. 

That is a remarkable twist in the game as now, you can't just focus on winning the small boards, you'll have to see where your next move sends your opponnent. In a way, you'll have to think multiple moves ahead.

Source: Quora

Now you know what mathematician do on picnics. And you know what computer engineers do? They probably write apps for things that mathematicians do. Yes, there is an app for this one too.

Kinda makes you rethink your own picnics, doesn't it?