It looks like the machine’s bishop was capturing the kid’s queen. Humans usually do that in one motion, bumping the bishop into the queen. Most of the machine’s

It looks like the machine’s bishop was capturing the kid’s queen. Humans usually do that in one motion, bumping the bishop into the queen. Most of the machine’s moves also are one motion, but its captures take two: 1) ensure that the destination square is clear, then 2) move the attacking piece. For all of typical games and most of this game, there’s a rhythm of alternating motions between players. After the machine’s first motion here, the kid absentmindedly continued the rhythm and made his next move, which was to capture the attacking bishop at its destination. The machine, naive to the anomaly, continued ensuring that the destination square was empty.