<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">\documentclass{ppex}
\nonstopmode
\usepackage [graph,frame]{xy}
\pagestyle{empty}
\setlength\textwidth{183.0pt}
\begin{document}
\ResetPreambleCommands
\ReadyForTheFray
\usepackage [graph,frame]{xy}
\[\xygraph{
[] *+[o]+[F]{1}
  (-[dl] *+=[o]+[F]{11}
  ,-[d]  *+=[o]+[F]{12}
    (-[dl] *+=[o]+[F]{121}
    ,-[d]  *+=[o]+[F]{122}
    ,-[dr] *+=[o]+[F]{123}
    )
  ,-[dr] *+=[o]+[F]{13}
  )
}\]
\end{document}
</pre></body></html>