A square $WXYZ$ is inscribed in a larger square $TUVW$ such that each vertex of $WXYZ$ lies on a distinct side of $TUVW$. If vertex $W$ divides side $\overline{TU}$ such that $TW=4\cdot WU$, what is the ratio of the area of the inner square $WXYZ$ to the area of the outer square $TUVW$?