1\documentclass{minimal} 2 3% Tikz 4\usepackage{pgf} 5\usepackage{tikz} 6 7\begin{document} 8 9\begin{center} 10 \begin{tikzpicture} 11 [ 12 vertex/.style={draw=none,circle,fill=black,minimum size=2pt}, 13 oedge/.style={->,>=latex,shorten >=6pt,draw,black,thick}, 14 roedge/.style={->,>=latex,shorten >=6pt,draw,black,thick,color=red} 15 ] 16 17\coordinate (V1) at (-3,3); 18\coordinate (V2) at (0,0); 19\coordinate (V3) at (0,6); 20\coordinate (V4) at (3,3); 21 22\path[oedge] ([yshift=3pt]V1) to ([yshift=3pt]V2) {}; 23\path[roedge] ([yshift=-3pt]V2) to ([yshift=-3pt]V1) {}; 24 25\path[roedge] ([yshift=3pt]V1) -- ([yshift=3pt]V3) {}; 26\path[oedge] ([yshift=-3pt]V3) -- ([yshift=-3pt]V1) {}; 27 28\path[oedge] ([xshift=2pt]V3) -- ([xshift=2pt]V2) {}; 29\path[oedge] ([xshift=-2pt]V2) -- ([xshift=-2pt]V3) {}; 30 31\path[oedge] ([yshift=3pt]V2) -- ([yshift=3pt]V4) {}; 32\path[roedge] ([yshift=-3pt]V4) -- ([yshift=-3pt]V2) {}; 33 34\path[roedge] ([yshift=3pt]V3) -- ([yshift=3pt]V4) {}; 35\path[oedge] ([yshift=-3pt]V4) -- ([yshift=-3pt]V3) {}; 36 37\node[vertex] at (V1) {}; 38\node[vertex] at (V2) {}; 39\node[vertex] at (V3) {}; 40\node[vertex] at (V4) {}; 41 42\draw[<-,>= latex,thick] (3.3,3) arc (0:320:94pt); 43 44 45\end{tikzpicture} 46\end{center} 47 48\end{document} 49