Animal Farm Lies and Deceit Quotes

How we cite our quotes: (Chapter.Paragraph)

Quote #10

But they had not gone twenty yards when they stopped short. An uproar of voices was coming from the farmhouse. They rushed back and looked through the window again. Yes, a violent quarrel was in progress. There were shoutings, bangings on the table, sharp suspicious glances, furious denials. The source of the trouble appeared to be that Napoleon and Mr. Pilkington had each played an ace of spades simultaneously. (10.34)

Our question: does this mean that one of them is playing fair? And if so, who? Or are they actually both cheating? Knowing Orwell, that last one seems most likely.