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Buttonholed!

Yesterday I played with Mobius strips with my daugter.

But after a day of playing with the strips - cutting them in half, and in half again, and figuring out the knots that result - she asked me "what other knots can we play with?"

So yesterday evening I got a pencil and some string and a small drill bit, and recreated this classic Sam Lloyd puzzle.

It is a great puzzle.

You can see my father-in-law struggling with it on the right...

Unimpressive?

The story according to Slocum is that Sam Lloyd invented the puzzle as a promotional item at the request of John McCall, the head of New York Life Insurance Co.

When Mr. McCall saw the simple stick and loop of string, he was unimpressed: "What's the purpose of it?" So then Sam passed the stick through a buttonhole on McCall's lapel, and bet a dollar that John would not be able to remove it.

After half an hour of struggling, McCall was still stuck with the stick. So Sam won the bet, New York Life Insurance gained a famous puzzle for its salesmen, and the term "to buttonhole" was born.

Five Minutes To Make, Hours to Solve

Here is how to make the puzzle:

1. Drill a small hole next to the eraser of a new pencil. (I used a 3/16" drill bit to bore through the soft wood.)
2. Loop a length of string through the hole
3. When you tie the loop, make sure that it is slightly shorter than the pencil, like so...

Here is how the pencil is passed through a buttonhole:

You might want to practice on your own before attaching the pencil to a victim's shirt, just to make sure you know how it works. Or else you may find yourself cutting your own string to get your pencil back.

How Did I Get Into This Mess?

Once you have identified your puzzle victim, you should definitely ask them to help you pull the pencil through the buttonhole to form the knot. The fact that it is so easy to attach the pencil makes it it all the more mind-boggling when you can't undo it.

After an hour or two, nobody in my family was able to solve the puzzle.

Except for surgeon Heidi, who had no trouble whatsoever with the knot. Even though she never saw me put the pencil on the buttonhole, it took her about 15 seconds to remove the pencil. Then again, she has a decade of experience with knotty three-dimensional situations in the O/R....

Posted by David at August 5, 2007 11:10 AM