% 1. Definition of characteristic points
\figinit{0.9pt}
\figpt 1:(-30,0)
\figpt 2:(170,60)
\figpt 3:(60,-40)
\figptorthoprojline 12:$H_3$=3/1,2/
\figptorthoprojline 13:$H_2$=2/1,3/
% 2. Creation of the graphical file
\psbeginfig{}
\psset(join=round)\psline[1,2,3,1]\psset(join=\defaultjoin)
\psaltitude 5[3,1,2]\psaltitude 5[2,3,1]
\psset arrowhead(ratio=0.2)\psnormal 20,0.5 [1,3]
\psarrowcircP 1;20 [3,2]
\psendfig
% 3. Writing text on the figure
\figvisu{\figBoxA}{}{
\figsetptname{$P_{#1}$}
\figwriten 1,2,12:(4)
\figwrites 3,13:(4)
\figptendnormal 4 :: 20,0.5 [1,3]\figwritew 4:$\vec{n}_2$(4)
}
\centerline{\box\figBoxA}