\documentclass{minimal}
\begin{document}

\command{
  a
  }{
  b
}

\begin{equation}
  \left(
    f(x) = 3
    \right)
    \left.
      f(x) = 3
      \right.
    \end{equation}

{
\graph[nodes={draw}
  test
]
}

\end{document}
