bundle environment

A tree is drawn by bundle environment. The bundle environment has one argument. This argument specifies the top node label. Leaves should be specified by \chunk in this environment.

If you write

\begin{bundle}{xxx}
\chunk{aaa}
\chunk{bbb}
\chunk{ccc}
\end{bundle}

You can nest the bundle environment. If you write

\begin{bundle}{xxx}
\chunk{aaa}
\chunk{
        \begin{bundle}{yyy}
        \chunk{bbb}
        \chunk{ddd}
        \end{bundle}}
\chunk{ccc}
\end{bundle}