\documentclass{ppex}
\nonstopmode
\usepackage {go}
\pagestyle{empty}
\setlength\textwidth{207.0pt}
\begin{document}
\ResetPreambleCommands
\ReadyForTheFray
\usepackage {go}
\inifulldiagram \gofontsize{20}
\pos{p}{5}=\black{.} \pos{q}{2}=\white{.}
\pos{o}{3}=\white{.} \pos{q}{3}=\white{.}
\pos{q}{4}=\white{.} \pos{q}{5}=\black{.}
\pos{r}{2}=\white{.} \pos{r}{3}=\black{.}
\pos{r}{4}=\black{.} \pos{r}{5}=\white{.}
\pos{r}{6}=\white{.} \pos{r}{7}=\white{.}
\pos{s}{1}=\white{\square}
\pos{s}{2}=\black{\triangle}
\pos{s}{3}=\letter{a} \pos{s}{4}=\black{.}
\pos{s}{5}=\black{.}  \pos{t}{1}=\black{2}
\pos{t}{2}=\white{1}  \pos{t}{3}=\black{.}
\pos{t}{4}=\letter{b}
\begin{center}
  \mbox{\showdiagram  n-t:1-8 }
\end{center}
\end{document}