Answer :
"By the toes of St. Moden," exclaimed Sir Hugh de
Fortibus
when this
puzzle was brought up, "my poor wit hath never shaped a more cunning
artifice or any more bewitching to look upon.
It came to me as in a
vision, and ofttimes have I marvelled at the thing, seeing its
exceeding
difficulty.
My masters and kinsmen, it is done in this wise."
The worthy knight
then pointed out that the
crescent was of a
particular
and somewhat irregular form—the two distances a
to b and c to d
being straight lines, and the arcs ac and bd
being precisely similar.
He showed that if the cuts be made as in Figure 1, the four pieces will
fit together and form a perfect square, as shown in Figure 2, if we
there
only regard the three curved lines.
By now making the straight cuts
also
shown in Figure 2, we get the ten pieces that fit together, as in
Figure
3, and form a perfectly symmetrical Greek cross.
The proportions of the
crescent and cross in
the original illustration were correct, and
the solution can be demonstrated to be absolutely exact and not merely
approximate.
I have a solution
in considerably fewer pieces,
but it is far
more
difficult to understand than the above method, in which the problem is
simplified by introducing the intermediate square
