Tournaments run with a time limit. After the time limit, the game ends in a set number of turns. There are also rules for &quot;slow play&quot; that generally keep a single turn from lasting too long—and inadvertently prevent certain weird combinations of cards from working.<p>Online play has what is effectively a chess clock. This doesn&#x27;t work in person because the game involves &quot;priority&quot; passing between players after <i>every single action</i>, which would be difficult to do manually. Additionally, play in person relies on a whole bunch of &quot;shortcuts&quot; that skip steps if both players don&#x27;t want to do anything, which would make timekeeping even more difficult.<p>But if you left out these tournament-specific rules and just played the <i>game</i> rules, you could have games going on arbitrarily long. Since you can create &quot;tokens&quot; you can have arbitrary amounts of state, so a game could even loop without ever hitting the same game state twice. (Think &quot;puffer trains&quot; from the John Conway&#x27;s Game of Life.)