\begin{center}
%\psset{unit=0.75}
\psset{SphericalCoor=true,viewpoint=50 -20 30,Decran=50}
\begin{pspicture*}(-5,-4)(6,9)
\psframe(-5,-4)(6,9)
\psSolid[object=grille,
   base=-5 5 -5 5,
   linecolor=gray]
%% create the pyramid with base area in xy-plane 
\psSolid[object=new,
   sommets=
      0 -2 0 %% 0
      -2 0 0 %% 1
      0 4 0  %% 2
      4 0 0  %% 3
      0 0 5, %% 4
   faces={
      [3 2 1 0]
      [4 0 3]
      [4 3 2]
      [4 2 1]
      [4 1 0]
   },
%% %% to create your pyramid, uncomment follow lines :
%% num=all,
%% show=all,
   action=draw,
   intersectiontype=0,
   intersectionplan={
      [0 0 1 -1]
      [0 0 1 -2]
   },
   intersectionlinewidth=1 2,
   intersectioncolor=(bleu) (rouge),
]
\end{pspicture*}
\end{center}