An Australian trial of two men on drug conspiracy charges was aborted after nearly three months and is on hold until a new jury can be called.

The reason for the wasted time and $947,000 in taxpayers’ money: Five of the jurors admitted to playing Sudoku, the number sequence game, instead of paying attention to testimony.

It was assumed the jurors had been taking very detailed notes, but the trial’s judge caught on when he saw some people were taking notes vertically, not horizontally.

One juror claimed the puzzle helped to keep his mind sharp: “Some of the evidence is rather drawn out and I find it difficult to maintain my attention the whole time.”

Next time you catch an employee or co-worker in the middle of a game of solitaire, remember that they’re just honing their skills before the next check run.