Improspectives

When I need to take a few minutes away from work, I’ll jump online for a couple of games of blitz chess (five minutes to make all moves) or play backgammon against my computer. I’ve also started doing logic problems, the kind of puzzle with grids and clues such as “The orange item took 10 minutes less to print than the yellow item.” I’m not great at them, but they do provide some distraction and, as a nerd, I’m happy when I figure one out.

I’m working through the Puzzle Baron series (currently on Book 3) and have noted some of the conventions the editor follows. One of those conventions is that the puzzle’s parameters, such as the color of an object, country, or date can’t provide a contextual clue to the correct answer. As an example, you wouldn’t have a guy named Richmond who turned out to be from Virginia because Richmond is the capitol of Virginia.

When the editor changes a clue to avoid contextual clashes, it can lead to some interesting discontinuities that provide a hint to the correct answer for a clue pair. In this instance, puzzle #7 in Puzzle Baron’s Logic Puzzles: Volume 3 contains just such an edit. The puzzle asks the solver to correctly assign the birthday, name, country of origin, and profession for a set of five passport applicants. The countries are Canada, France, Norway, South Africa, and Sweden, while the birthdays fall on April 13, May 18, June 14, July 16, and August 15. It’s conventional for the days and months to occur in sequence so you can give clues such as “The applicant from Norway was born one month earlier than the applicant from Sweden.” Days are often sequentially numbered as well, but in this case the months were used as levers and the days were not, so the day numbers could be changed if desired.

The oddity that made me say “That’s funny…” is the May 18 date. The other four day numbers are in sequence from 13 to 16, which makes the May 18 date stand out. I have a number of Norwegian friends, so I happen to know that May 17 is Norwegian National Day. Based on that knowledge, I assumed that the applicant from Norway would have the May 18 birthday because, if it had fallen on May 17, there would be external context to guide the solver to the correct answer. Sure enough, that’s how the puzzle worked out.

If the editor changed the date rather than the name of the country to leave an Easter egg for solvers, it’s an excellent gesture that in no way detracted from the fun I had solving the puzzle. If the change was unintentional, it’s a reminder of how seemingly irrelevant changes can make a big difference. It could have been a total accident, of course, but it’s still a cool story.