68. Given an equilateral triangle $A B C$. On the extensions of its sides $A B$ and $A C$ beyond points $B$ and $C$, points $D$ and $E$ are taken such that $|B D| \cdot|C E|=|B C|^{2}$. Find the geometric locus of the points of intersection of the lines $D C$ and $B E$.
68. The desired set is the arc $B C$ of the circumcircle of $\triangle A B C$, corresponding to a central angle of $120^{\circ}$.