ABSTRACT
Everyone who has ever tried to solve Loyd's "14-15" puzzle very soon felt
an invisible force that prevents a solution. A n d this force is so stubborn,
so strong, that one might continue attempts to eternity without success.
Everyone who has ever tried to solve Loyd's "14-15" puzzle very soon felt
an invisible force that prevents a solution. A n d this force is so stubborn,
so strong, that one might continue attempts to eternity without success.