text.mod/graphviz.mod/graphviz/tests/graphs/dfd.ps

/xdef {exch def} bind def
/DFDbox {
	10 dict begin
		/fflag xdef
		/sides xdef
		dup
		aload pop
		% draw the sides
		newpath
		moveto
		1 1 sides {
			2 mod 0 ne
			{moveto} % even sides
			{lineto currentpoint stroke moveto} % odd sides
			ifelse
		} for
		fflag   % if shape is filled
		{
			aload pop
			newpath
			moveto
			/y1 xdef
			/x1 xdef
			lineto stroke newpath
			x1 y1 moveto lineto stroke
			pop pop
		}
		{pop}
		ifelse
	end
} bind def