The 6.1 version of O & X for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The actual developer of this free software for Mac is Nicholas Dean. O & X for Mac is included in Games. According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software.
From the developer:
O & X lets you play the classic tic-tac-toe game against your friends either online or locally on the same screen. You challenge one of the many computer players to see how good you really are. You can unlock a multitude of different pieces to show off your skill to your opponents. You can compare your abilities with those of friends through the Game Center leaderboards and achievements.
You may want to check out more Mac applications, such as Treasure Chess, 3D Reversi Deluxe or Ataxx, which might be similar to O & X.