Spoiler Alert: This blog recounts the solving of a classic logic puzzle, attributed in this version to Einstein. If you want to try it yourself first, stop reading now and either Google the puzzle or click here for the puzzle’s full text.
“Who owns the FISH?”
I stare at the mess of yellow stickies on my airplane tray. I’ve been working on this puzzle for a good long while but I feel no nearer to answering the question.
Oh, I know who lives in the RED house, and who drinks TEA. I know that the NORWEGIAN lives in the first house, and where the GREEN house is relative to the WHITE one. I know these things because I have been told them. I even know a few things I have not been told. But I do not know who owns the FISH.
I look at my sheet again.
“There are five houses in five different colours in a row. In each house lives a person with a different nationality. The five owners drink a certain type of beverage, smoke a certain brand of cigar and keep a certain pet. No owners have the same pet, smoke the same brand of cigar, or drink the same beverage.”
Other than this preamble, there are 15 facts provided: too many to hold in my head at one go, yet somehow too few to enable solving by inspection. To the rescue: some small stickies and a pad of paper.
After recording all the elements (house colours, nationalities, beverages, cigars, pets) on stickies, I begin to work my way through the 15 facts.
“The Brit lives in the red house.” I link the BRIT and RED stickies.
“The Dane drinks tea.” I link the DANE and TEA stickies.
I’m silently congratulating myself on my cleverness when I hit a snag.
“The owner of the middle house drinks MILK.”
Hmm. There is no other stickie to which I can link MILK, so I put it somewhere in the centre of the page.
What’s next? “The Norwegian lives in the first house.” All right then: NORWEGIAN goes on the far left.
By the time I’ve gone through all 15 facts, I have only three stickies placed on my sheet—NORWEGIAN, BLUE, and MILK—and I have a mitt-full of linked stickies, off to one side. What now?
I look at the NORWEGIAN. Can I figure out the colour of his or her house by elimination?
- It can’t be BLUE – that’s the house next door.
- It can’t be RED – that house belongs to the BRIT.
- It can’t be GREEN or WHITE – those houses are side by each, and the BLUE house next door makes that impossible.
Aha! It must be YELLOW. That gives me the cigar for that owner, too: DUNHILL.
And so it goes, step by step, slowly. At one point, well into the puzzle and temporarily stumped for the next move, I look at my muddle of linked stickies, arranged in no particular order, and realize that this puzzle wants more than stickies: It wants a grid.
Eventually solving the puzzle, I gaze lovingly at my handiwork for a moment.
But only for a moment. Then I peel all the stickies off, line them up by category again, make a grid on a fresh piece of paper, and start working the puzzle again.
I may as well be starting anew. I half-remember my approach, of course, but only half. I do better mostly because the grid makes it easier:
- Easier to record positional information
- Easier to see information gaps and constraints
- Easier to record deductions in an organized way
As I finish the puzzle for the second time, I’m feeling pretty good. I have solved a puzzle that Einstein figured only 1% of the population could solve, and I have solved how to solve it.
My self-satisfaction lasts no longer than a visit with Google. The Einstein attribution is dodgy; Einstein’s alleged assessment of its difficulty is unsupported altogether.
Worse is to come. Over the next few days I show this puzzle to some kids aged 9 to 12. I let them look at it for a few minutes, I show them the stickies and grid, I ask one leading question to illustrate the elimination method, and then I watch as they work their way through to the correct solution. Pretty quickly, dagnab it.
So what did I learn? Well, a few things:
- How I organize information matters, especially when reasoning my way through puzzles built to require this skill.
- Life would be easier if more of my problems were logical puzzles with a single right answer.
- Kids are really irritating.