\documentclass{article}
\usepackage{gastex}

\begin{document}

% Tricks: multiput and variables

\begin{center}
  \unitlength=0.7mm
\begin{picture}(60,46)(0,-3)
%   \put(0,-3){\framebox(60,46){}}
  {\gasset{AHnb=0}
    \drawline(0,0)(60,0)
    \drawline(0,20)(60,20)
    \drawline(0,40)(60,40)}
  \gasset{Nw=1.5,Nh=1.5,Nframe=n,Nfill=y}
  \multiput(0,0)(10,0){5}{%
    \node(A)(0,0){}\node(B)(5,20){}
    \drawedge(A,B){}
    }
  \multiput(10,20)(10,0){5}{%
    \node(A)(0,0){}\node(B)(5,20){}
    \drawedge(A,B){}
    }
\end{picture}
  \qquad
  \unitlength=1mm
\begin{picture}(50,30)(-5,0)
%   \put(-5,0){\framebox(50,30){}}
  \def\ax{5}\def\ay{5}\def\bx{35}\def\by{25}%
  \node(a)(\ax,\ay){$a$}\node(b)(\bx,\by){$b$}
  \drawedge(a,b){}
  \drawloop[loopdiam=6,loopangle=180](a){}
  \drawloop[loopdiam=6,loopangle=0](b){}

  \def\ax{5}\def\ay{25}\def\bx{35}\def\by{5}%
  \node(a)(\ax,\ay){$a$}\node(b)(\bx,\by){$b$}
  \drawedge(a,b){}
  \drawloop[loopdiam=6,loopangle=180](a){}
  \drawloop[loopdiam=6,loopangle=0](b){}
\end{picture}
\end{center}

\end{document}