You’ve spotted the 16 in the corner of a Kakuro grid. Two cells, so it’s 7 and 9. You pencil “7 9” into both cells and feel good about it for about four seconds. Then you notice the 17 next to it is “8 9” in both cells too, and the 24 below is “7 8 9” …

You found the 3 in the corner of your Kakuro grid. Two cells, so it’s a 1 and a 2. You penciled both digits into both cells and felt good about it. Now you’re staring at those two cells, pencil hovering, and the question is simple: which one gets the 1?

You could flip a coin. Half the …