\begin{align*}
x(u,v) &= 3\cos u\sin v, \\[2.5pt]
y(u,v) &= 3\sin u\sin v, \\
z(u,v) &= 3\left(
\cos v + \ln\left(\tan\left(\frac{v}{2}\right)\right)
\right)+\frac{u}{4}
\end{align*}
\begin{align*}
x(u,v) &= u\cos v, \\
y(u,v) &= u\sin v, \\
z(u,v) &= u/3
\end{align*}
\begin{align*}
x(u,v) &= (3 + \cos u)\cos v, \\
y(u,v) &= (3 + \cos u)\sin v, \\
z(u,v) &= \sin u
\end{align*}
\begin{align*}
x(u,v) &= (1 + \tfrac{1}{5}\sin(5u)\sin(5v))\sin v\cos u, \\
y(u,v) &= (1 + \tfrac{1}{5}\sin(5u)\sin(5v))\sin v\sin u, \\
z(u,v) &= (1 + \tfrac{1}{5}\sin(5u)\sin(5v))\cos v
\end{align*}
\begin{align*}
x(u,v) &= (1+\dfrac{v}{2}\cos\dfrac{u}{2})\cos u, \\
y(u,v) &= (1+\dfrac{v}{2}\cos\dfrac{u}{2})\sin u, \\
z(u,v) &= \dfrac{v}{2}\sin\dfrac{u}{2}
\end{align*}
\begin{align*}
x(u,v) &= u(1-u^2/3+v^2)/2, \\
y(u,v) &= -v(1-v^2/3+u^2)/2, \\
z(u,v) &= (u^2-v^2)/2
\end{align*}