\( \boldsymbol{x}(u, v) = \begin{pmatrix} (R + r \cos u) \cos v \\ (R + r \cos u) \sin v \\ r \sin u \end{pmatrix} \)

\( (0 \leq u \leq 2 \pi, \, 0 \leq v \leq 2 \pi) \)

\( R = \) , \( r = \) 更新

\( (0.1 \leq r < R \leq 10) \)