Show HN: UltraXOXO – a tic-tac-toe of tic-tac-toe's

It's a surprisingly challenging version of tic-tac-toe. It has similarities to chess, yet much more approachable.

It's a big XO board made up of 9 smaller XO boards. You need to win the bigger XO board, by winning 3-straight smaller XO boards.

There are just 2 rules: 1) If X plays in, say, cell N in a small board, then O must play in the cell N of the bigger board.

2) If cell N of the bigger board is full, players gets a free turn - they can place wherever they like.

I did not invent this format. Found it on a reel and played on pen-paper with a friend in flight (highly recommended). It did feel like a project to get started with vibe coding. So yes, do expect some visual bugs.

The 'bot' is decently sharp. It thinks 2 steps ahead and uses some basic heuristics.

Do share screenshots/browser details if you want to report a bug. Tell me how many turns it took you to win/lose :)