\( \boldsymbol{x}(u, v) = \begin{pmatrix} \cos u \hskip 0.1em \cos v \\ \cos u \hskip 0.1em \sin v \\ \sin u \end{pmatrix} \)

\( \left( - \dfrac{4 \pi}{9} \leq u \leq \dfrac{4 \pi}{9}, \, 0 \leq v \leq 2 \pi \right) \)