\documentclass{article}
\usepackage[usenames]{color}
\usepackage{gastex}

\begin{document}

% Compatibility with pspictpg

\begin{center}\compatiblepspictpg
\begin{picture}(80,80)(-40,-40)
% \put(-40,-40){\framebox(80,80){}}
  \drawvector(-40,0)(40,0)
  \drawvector(0,-40)(0,40)
  \drawline(-30,-30)(30,30)
  \cbeziervector(-30,-20)(-30,0)(-10,0)(-10,20)
  {\setpsdash(3)\cbezier(-30,20)(-30,0)(-10,0)(-10,-20)}
  \qbeziervector(1,-20)(20,-20)(20,-1)
  \qbezier(1,-20)(1,-1)(20,-1)
  \drawcircle(10,30)(10)
  \put(-20,-30){\circle{10}}
  \put(25,5){\line(1,3){8}}
  \put(25,5){\vector(1,2){8}}
  \setpsgray{0.5}
  \drawdisk(-30,30)(10)
  \put(20,-30){\circle*{10}}
\end{picture}
\end{center}

\end{document}