\documentclass[a4paper]{article}

\usepackage[pdf]{dottex}

\begin{document}

\begin{dotpic}[width=.5\textwidth]
	a -> b;
	a -> c;
	b -> d;
	d -> a;
\end{dotpic}

\begin{neatopic}
	a -- b;
	b -- c;
	a -- g;
	e -- f;
	g -- c;
\end{neatopic}

\end{document}
