There is a new puzzle named the "Bottleneck" from a company called
Groton Ltd. in Fitchburg, MA. It looks impossible to solve but they
claim it can be done. It consists of an ordinary glass bottle and a
solid plastic rod which fits closely within the bottle. There is a
marble in the bottle but the rod is held in the bottle by a screw
and nut as shown below:

     |   |
     |   |
     |   |
    ||   ||
    ||   ||
    ||   ||
   / |   | \
  /  |   |  \
 /   |   |   \
|    |   |    |
|    |   |    |
|    |   |    |
| |==|===|=|| |    ----  Threaded screw and nut go thru threaded rod
|    |   |    |
|    |   |    |
|             |
|   __        |
|  (  )       |    ----  Marble
---------------

The object is to remove the marble. It is fairly easy to remove the nut
but it is very difficult to turn the screw. It apparantly can be done
without inserting a tool between the bottleneck and the rod.

It costs about $10.00 and is available from Games People Play in Cambridge
and Miscellanea in Acton. Has anyone tried it?