Spacing's not perfect and it's using a full brace in both halves rather than some kind of half brace but it might get you started.

\documentclass{article} \setlength\textheight{.4\textheight} \usepackage{color,graphicx} \newcounter{setc} \newcounter{subsetc}[setc] \newenvironment{subsetlist} {\par\addvspace\bigskipamount\delimitershortfall-1em \refstepcounter{subsetc}% \noindent$\mathop{\rotatebox[origin=c]{-90}{\color{red} Subset -- \thesubsetc}}\color{green}\left\{\color{black}\begin{minipage}{.6\textwidth}\itemize} {\enditemize\end{minipage}\right.$% \par\addvspace\bigskipamount} %\noindent$\mathop{\rotatebox[origin=c]{-90}{\color{red} Set -- \thesubsetc}}\color{green}\left\{\color{black}\begin{minipage}{.6\textwidth}\itemize} \newenvironment{setlist} {\par\mbox{}\par \setbox0\vbox\bgroup\hsize.7\textwidth \refstepcounter{setc}}% {\egroup \ifdim\ht0>\dimexpr\pagegoal-\pagetotal\relax \setbox2\vsplit0 to \dimexpr 0.7\pagegoal-0.7\pagetotal\relax \noindent$\mathop{\rotatebox[origin=c]{-90}{\color{red} Set -- \thesetc\ \ldots}}\color{green}% \left\{\color{black}\vcenter{\box2}\right.$% \par \noindent$\mathop{\rotatebox[origin=c]{-90}{\color{red}\ldots\ Set -- \thesetc}}\color{green}\left\{\color{black}\vcenter{\box0}\right.$% \else \noindent$\mathop{\rotatebox[origin=c]{-90}{\color{red}\ldots\ Set -- \thesetc}}\color{green}\left\{\color{black}\vcenter{\box0}\right.$% \fi } \begin{document} \begin{setlist} \begin{subsetlist} \item aaa \item bbb \item ccc \end{subsetlist} \begin{subsetlist} \item aaa \item ccc \item bbb \end{subsetlist} \begin{subsetlist} \item aaa \item ccc \item bbb \end{subsetlist} \begin{subsetlist} \item aaa \item ccc \item bbb \end{subsetlist} \begin{subsetlist} \item aaa \item ccc \item bbb \end{subsetlist} \end{setlist} \end{document}