The Einstein Puzzle

From StoneHome

I've taken the liberty of rephrasing this, as Einstein was a brilliant physicist, but not much of a game designer. The game itself remains intact; I've made some new word choices to make the rules clearer, and to be rid of the "extra rules" people typically add to clarify those things that someone inevitably asks like "how do I know the houses are in order?," and so on. I've also added just a pinch of setting, to make it easier to visualize the original problem's ruleset in one's head. No information significant to the puzzle itself has been added; it's a question of "five men are discussing over dinner," instead of "there are five men." Easier on the imagination, nothing more.

I've also taken the liberty of switching the information pools; instead of nationality we use first names now, because it's easier to think about Alvin and Bill than it is The German and The Brit. Similarly, I've replaced brands of tobacco with styles of tobacco; instead of Dunhill and Pall Mall, it's now cigars and cigarettes. The original puzzle, including a good set of the common added rules, can be found here. In case you're wondering why I called it "El Cigar" instead of just "Cigar" and "Oral Pouch" instead of "Pouch" or "Chew," I find puzzles like this easier when all information has a unique first letter; it makes writing relations out faster.

Einstein is quoted not only as creating this puzzle, but also claiming that only 2% of people would be able to solve it. I don't actually know if that's true or an urban myth, but in my experience I've come to believe that puzzles like this aren't hard enough to break all but one in fifty people, if they actually want to finish. That said, the puzzle is difficult enough even once you've figured out how to solve it to provide a brief and entertaining distraction.

Unfortunately, the puzzle isn't such that you can just switch a few numbers and play again; there is a moderate amount of real-world decision making involved in creating one of these puzzles. Fortunately, I'm a psychopath, so I just taught PHP to make them for me.

The Einstein Puzzle

Five men sit at a table at a resteraunt, having drinks. They have an ongoing game with a cute young graduate student waitress; the men are mathematicians from the local college and are good sports, and since grad students in menial jobs rarely have enough money, they've established an ongoing bet, where if the student can figure out some or another puzzle they give at the beginning of the meal by the time to pay the check, they'll double her tip; if she can't, they won't tip her at all. (She's smart, and wins more often than she loses, so it's good fun for all.)

This evening, one of the mathematicians has done himself proud. He's found simple information about all five of them, and arranged relationships within that information so that with work, one can find the missing piece of information. It so happens that all five men are in a row in the offices, since they're old tenured professors who've been around since the beginning of time (hence going out for a traditional drink together.) Since the theater department is just down the hall, a few weeks ago a practical joke ended with every door in the office painted a different color. Also, each man has a different kind of pet, a different favorite beverage, a different way of using tobacco, and has a different first name.

It's worth noting that the graduate student waitress is a philosophy student, and therefore though she's quite good with logic, she's never been within a hundred feet of a math office, so she doesn't know which teacher has which office door. Also, the professors have a glass of wine with dinner, so she can't guess whose drink is what from their orders at the resteraunt.

The goal of the puzzle is simple. Given a set of lists - names, drinks, et cetera - and a set of fifteen relationships, discover who keeps a fish as a pet.

Data

The mathematicians give her the following information:

• Lists
  • Our names are "Alvin, Bill, Chuck, David and Edward."
  • Our office doors have been painted red, yellow, green, blue, or white
  • We keep either a cat, a dog, a fish, a bird, or a horse as a pet
  • We smoke either cigarettes, El Cigar, a pipe, chew oral pouches, or don't smoke
  • We drink either coffee, tea, milk, water, or beer
• Relationships
  • Alvin has the red office door
  • Edward keeps dogs as pets.
  • Bill drinks tea.
  • The green office door is to the left of the white office door
  • The green office's occupant drinks coffee.
  • The person who chews an oral pouch keeps birds as pets.
  • The yellow office's occupant smokes El Cigar.
  • The man who works in the center office drinks milk.
  • David works in the first (leftmost) office.
  • The man doesn't smoke has an office next door to the man who keeps cats as pets.
  • The man who keeps the horse works next to the man who smokes El Cigar.
  • The man who smokes cigarettes drinks beer.
  • Chuck smokes a pipe.
  • David's office is next door to the office with a blue door.
  • The man doesn't smoke has a neighbor who drinks water.

Goal

Who keeps the fish?

Remapping the Original Puzzle

To recreate the original puzzle, you'll need to replace the names with nationalities, and the tobacco forms with tobacco brands. Make the following changes:

• Names to Nationalities (alphabetic order mapping)
  • Alvin becomes The Brit
  • Bill becomes The Dane
  • Chuck becomes The German
  • David becomes The Norwegian
  • Edward becomes The Swede
• Tobacco styles to brands
  • Cigarette becomes Bluemasters
  • Doesn't Smoke becomes Blends
  • El Cigar becomes Dunhill
  • Oral Pouch becomes Pall Mall
  • Pipe becomes Prince
• The office door colors are rephrased house colors, because consecutive offices are more likely than consecutive homes.

Solution

Want to check your answer? Giving up? You can find a solution here.