Jacob's Revenge, alternative solution

[tc...@lsa.umich.edu]

Jacob's Revenge is a well-known puzzle that you can easily find on the web:

http://www.elversonpuzzle.com/jacob.html
http://www.brainpuzzles.com/Elverson/winebottle.html

I will not spoil the puzzle by describing the intended solution here.
What I *do* describe below is something that a friend of mine (David
Moulton) discovered, which is an alternative to the intended solution.

Note a subtle difference between the pictures of the puzzles on the
above two websites. In one case, the big stick has a groove near one
end and a smaller cross-stick near the other end. In the other case,
the big stick is symmetrical in the sense that it has grooves near both
ends and no cross-stick.

The alternative solution works on the cross-stick version, or at least
on my specimen of it. I don't know if a variant can be made to work on
the other version. Perhaps someone who owns the other version can try
it out and report the results.

The alternative solution begins by getting the puzzle into the following
configuration. The bottle should be horizontal. The big stick should
have one end resting against the bottom (i.e., the end opposite the cork)
of the bottle. The big stick should lean against the "side" of the
bottle; i.e., the cross-stick should be as vertical as you can make it.
This relies on friction between the stick and the bottle, and requires
some dexterity since the big stick will tend to slip down the side of
the bottle so that the cross-stick is horizontal. The ball should rest
against the cross-stick, on the side nearer the cork, and on the upper
side of the big stick. ("Upper side" has a meaning because of the way
the big stick is leaning against the side of the bottle.)

Now what you need to do is to tilt the bottle so that the ball rolls
quickly along the big stick towards the cork---but don't allow the big
stick to move off the bottom of the bottle. It requires dexterity to
get this just right, but if you do, the ball will be able to get past
the groove in the big stick and reach the cork.

Is this alternative solution known?

When I went back some months later to the store where I bought my Jacob's
Revenge, I noticed that they were only selling the double-groove version.
My theory at the time was that the double-groove version was easier to
manufacture---since the cross-stick is bigger than the opening of the
bottle, it has an "impossible object" flavor to it and is presumably more
difficult to manufacture. However, perhaps another reason is that the
alternative solution was discovered and they wished to eliminate it?
--
Tim Chow tchow-at-alum-dot-mit-dot-edu
The range of our projectiles---even ... the artillery---however great, will
never exceed four of those miles of which as many thousand separate us from
the center of the earth. ---Galileo, Dialogues Concerning Two New Sciences

[Carl G.]

<tc...@lsa.umich.edu> wrote in message
news:4447da6c$0$571$b45e...@senator-bedfellow.mit.edu...

> Jacob's Revenge is a well-known puzzle that you can easily find on the
web:
>
> http://www.elversonpuzzle.com/jacob.html
> http://www.brainpuzzles.com/Elverson/winebottle.html
>
> I will not spoil the puzzle by describing the intended solution here.
> What I *do* describe below is something that a friend of mine (David
> Moulton) discovered, which is an alternative to the intended solution.

...

In the cross-stick version I have, the cross-stick is held in place with a
small nail, which is nailed into the end of the long stick. I remember
trying to solve the puzzle using a strong magnet to hold the sticks against
the bottom of the bottle via the nail (as an alternative solution, since I
had worked out the "standard solution" before I bought the puzzle). The
magnets I had available at the time were not strong enough, but I heard
rumors that others had been able to solve the puzzle using a strong magnet.
Can anyone confirm that the magnet solution has been used successfully?

Carl G.