[Illustration]
Here is a curious mechanical puzzle that was given to me some years ago,
but I cannot say who first invented it. It consists of two solid blocks
of wood securely dovetailed together. On the other two vertical sides
that are not visible the appearance is precisely the same as on those
shown. How were the pieces put together? When I published this little
puzzle in a London newspaper I received (though they were unsolicited)
quite a stack of models, in oak, in teak, in mahogany, rosewood,
satinwood, elm, and deal; some half a foot in length, and others varying
in size right down to a delicate little model about half an inch square.
It seemed to create considerable interest.