\begin{figure}[!ht]
\setlength{\unitlength}{.7cm}

\begin{center}
\begin{picture}(19,9)(0,0) \label{fig-sol1}
\linethickness{.1pt}

\multiput(3,2)(1,0){3}{\circle{.3}}

\multiput(3,3)(1,0){3}{\circle{.3}}

\multiput(1,4)(1,0){7}{\circle{.3}}

\multiput(1,5)(1,0){7}{\circle{.3}}

\multiput(1,6)(1,0){7}{\circle{.3}}

\multiput(3,7)(1,0){3}{\circle{.3}}

\multiput(3,8)(1,0){3}{\circle{.3}}

\put(2.5,1.5){\line(0,1){2}} \put(2.5,3.5){\line(-1,0){2}} \put(.5,3.5){\line(0,1){3}}
\put(.5,6.5){\line(1,0){2}} \put(2.5,6.5){\line(0,1){2}} \put(2.5,8.5){\line(1,0){3}}
\put(5.5,8.5){\line(0,-1){2}} \put(5.5,6.5){\line(1,0){2}} \put(7.5,6.5){\line(0,-1){3}}
\put(7.5,3.5){\line(-1,0){2}} \put(5.5,3.5){\line(0,-1){2}} \put(5.5,1.5){\line(-1,0){3}}


\put(2,4){\circle*{.2}} \put(3,4){\circle*{.2}} \qbezier(2,4)(3,4.7)(4,4) \put(4,4){\vector(1,-1){0}}

\put(3,5){\circle*{.2}} \put(3,6){\circle*{.2}} \qbezier(3,5)(2.5,6)(3,7) \put(3,7){\vector(1,1){0}}

\put(7,6){\circle*{.2}} \put(6,6){\circle*{.2}} \qbezier(7,6)(6,6.5)(5,6) \put(5,6){\vector(-1,-1){0}}

\put(5,5){\circle*{.2}} \put(5,4){\circle*{.2}} \qbezier(5,5)(5.5,4)(5,3) \put(5,3){\vector(-1,-1){0}}


\multiput(13,2)(1,0){3}{\circle{.3}}

\multiput(13,3)(1,0){3}{\circle{.3}}

\multiput(11,4)(1,0){7}{\circle{.3}}

\multiput(11,5)(1,0){7}{\circle{.3}}

\multiput(11,6)(1,0){7}{\circle{.3}}

\multiput(13,7)(1,0){3}{\circle{.3}}

\multiput(13,8)(1,0){3}{\circle{.3}}

\put(12.5,1.5){\line(0,1){2}} \put(12.5,3.5){\line(-1,0){2}} \put(10.5,3.5){\line(0,1){3}}
\put(10.5,6.5){\line(1,0){2}} \put(12.5,6.5){\line(0,1){2}} \put(12.5,8.5){\line(1,0){3}}
\put(15.5,8.5){\line(0,-1){2}} \put(15.5,6.5){\line(1,0){2}} \put(17.5,6.5){\line(0,-1){3}}
\put(17.5,3.5){\line(-1,0){2}} \put(15.5,3.5){\line(0,-1){2}} \put(15.5,1.5){\line(-1,0){3}}


\put(14,4){\circle*{.2}} \put(13,7){\circle*{.2}} \put(15,6){\circle*{.2}} \put(15,3){\circle*{.2}}


\end{picture}
\end{center}
\end{figure}
