\documentclass{article}
\usepackage{pst-node}
\usepackage{pstricks-add}
\pagestyle{empty}

\begin{document}

\begin{pspicture}(10,7)
  \psgrid[subgriddiv=0,griddots=10,gridcolor=gray,gridlabels=7pt]
  \psset{linewidth=1mm,radius=0.5}
  \Cnode(4,3){A}
  \Cnode(6,2){B}
  \Cnode(4,6){C}
  \Cnode(3,0){D}
  \SpecialCoor
  \psline[linestyle=dashed,linewidth=0.1pt](A)(B)(C)(D)(B)
  \psline[linestyle=dashed,linewidth=0.1pt](C)(A)(D)
  \psline[linestyle=dashed,linewidth=0.1pt](0,2)(10,2)
  \psline[linestyle=dashed,linewidth=0.1pt](0,3)(10,3)
  \psline[linestyle=dashed,linewidth=0.1pt](0,5)(10,0)
  \psline(A)(B)
  \psline[linecolor=red](C)([Xnodesep=4]A)
  \psline[linecolor=green](C)([nodesep=4]A)
  \psline[linecolor=cyan](C)([Xnodesep=3]{A}B)
  \psline[linecolor=blue](C)([Ynodesep=3]{A}B)
  \psline[linecolor=magenta](C)([Ynodesep=3]{B}A)
  \psline[linecolor=yellow](C)([Xnodesep=3]{B}A)
  \psline{->}([Xnodesep=4]{A}B)([Ynodesep=5]{D}C)
\end{pspicture}

\end{document}
