% arara: indent: {overwrite: yes}
\documentclass[pstricks,border=12pt]{standalone}
\usepackage{pst-node}
\addtopsstyle{gridstyle}{gridlabels=0pt,strokeopacity=.25}

\begin{document}
\begin{pspicture}[showgrid=top](8,8)
	\multips(0,.5)(0,1){8}{%
		\multips(.5,0)(1,0){8}{%
			\psline[linecolor=red](6pt;-135)(6pt;45)
			\psline[linecolor=red](6pt;135)(6pt;-45)}}
	\pscustom
	[
		dimen=middle,
		fillstyle=eovlines*,
		fillcolor=white,
		hatchcolor=blue,
		linecolor=blue,
	]
	{
		\psframe(8,8)
		\pspolygon
		(3,1)
		(3,4)
		(1,4)
		(1,6)
		(2,6)
		(2,7)
		(7,7)
		(7,4)
		(6,4)
		(6,6)
		(5,6)
		(5,4)
		(6,4)
		(6,3)
		(7,3)
		(7,1)
		(6,1)
		(6,2)
		(5,2)
		(5,1)
	}
	\psset{linecolor=blue,nodesep=7pt}
	\pscircle*(4,2){2pt}
	\pscircle*(4,3){2pt}
	\pcline(4,2)(4,3)
\end{pspicture}
\end{document}