\documentclass{article}
\usepackage{gastex}

\begin{document}

% Arrowheads

\begin{center}
\begin{picture}(60,40)(-30,-17)
\put(-30,-17){\framebox(60,40){}}
  \node[Nframe=n](A)(-15,20){}\node[Nframe=n](B)(15,20){}
  \drawedge[AHangle=30,AHLength=3,AHlength=0](A,B){}
  \drawedge[AHangle=90,AHLength=2,AHlength=0](B,A){}
 
  \node[Nframe=n](A)(-15,15){}\node[Nframe=n](B)(15,15){}
  \drawedge[AHnb=2](A,B){}
  \drawedge[AHnb=2](B,A){}
 
  \node[Nframe=n](A)(-15,10){}\node[Nframe=n](B)(15,10){}
  \drawedge[AHnb=2,AHangle=30,AHLength=3,AHlength=0,AHdist=1](A,B){}
  \drawedge[AHnb=2,AHangle=30,AHLength=3,AHlength=0,AHdist=1](B,A){}
 
  \node[Nframe=n](A)(-15,5){}\node[Nframe=n](B)(15,5){}
  \drawedge[AHnb=2,AHangle=30,AHLength=3,AHlength=0,AHdist=-1](A,B){}
  \drawedge[AHnb=2,AHangle=30,AHLength=3,AHlength=0,AHdist=-1](B,A){}
 
  \node[Nframe=n](A)(-15,0){}\node[Nframe=n](B)(15,0){}
  \drawedge[AHnb=2,AHangle=30,AHLength=3,AHlength=0,AHdist=-1](A,B){}
  \drawedge[AHnb=2,AHangle=210,AHLength=3,AHlength=0,AHdist=-1](B,A){}

  \node(A)(-15,-10){}\node(B)( 15,-10){}

  \drawbpedge[AHnb=6](A,60,25,B,240,25){}
  \drawbpedge[AHnb=6](B,240,25,A,60,25){}
  \gasset{AHnb=1,AHangle=30,AHLength=3,AHlength=0}
  \drawloop[loopangle=180](A){}
  \gasset{AHnb=3,AHangle=30,AHLength=3,AHlength=1.5,AHdist=1.8}
  \drawloop[loopangle=0](B){}
\end{picture}
\end{center}

\end{document}