fig013_ruf.pgf

% (c) 2012 Dimitrios Vrettos - d.vrettos@gmail.com
\begin{tikzpicture}[font=\small,x=8mm, y=8mm, minimum size=10mm]

\node (a0) at (0,0) {};
\node (a1) at (1,0) {1};
\node (a2) at (2,0) {$-3$};
\node (a3) at (3,0) {1};

\node(a4) at (0,-1) {1};
\node (a5) at (1,-1) {};
\node (a6) at (2,-1) {};
\node (a7) at (3,-1) {};

\node (a8) at (0,-2) {};
\node (a9) at (1,-2) {1};
\node (a10) at (2,-2) {};
\node (a11) at (3,-2) {};

\draw (a0.north east)--(a8.south east);
 \draw (a4.south west)--(a7.south east);
\draw (a2.north east)--(a10.south east);

\draw[->,red] (a1.south)--(a9.north);

\end{tikzpicture}