\documentclass{ppex}
\nonstopmode
\usepackage [frame]{xy}
\pagestyle{empty}

\begin{document}
\ResetPreambleCommands
\ReadyForTheFray
\usepackage [frame]{xy}
\[
\newcommand{\smbf}{\small\bfseries}  \newcommand{\smit}{\small\itshape}
\begin{xy}
 0*=(22,14)!UR!(-10,-8)[F]\txt\smbf{center\\of box}="box";
  "box"+L*+!R\txt\small{Left\\side}
 ,"box"+R*+!L\txt\small{Right\\side}
 ,"box"+D*+!U\txt\small{Bottom side}
 ,"box"+U*+!D\txt\small{Top side}
 ,"box"+LD*@{*}*+!RU\txt<2cm>\smit{Lower left diagonal}
 ,"box"+RD*@{*}*+!LU\txt<2cm>\smit{Lower right diagonal}
 ,"box"+LU*@{*}*+!RD\txt<2cm>\smit{Upper left diagonal}
 ,"box"+RU*@{*}*+!LD\txt<2cm>\smit{Upper right diagonal}
\end{xy}\]
\end{document}