\documentclass[pstricks]{standalone}
\usepackage{pst-solides3d,pst-contourplot}
\begin{document}

\begin{pspicture}(-5,-5)(5,5)
% Julien Royer
% https://www.math.univ-toulouse.fr/~jroyer/TD/2015-16-L2PS/L2PS-poly.pdf
\psframe(-5,-5)(5,5)
\multido{\n=-2.0+.2,\nH=0.0+0.05}{20}{
\psContourPlot[unit=1,a=0.05,algebraic,function=sin(x)-sin(y)-\n,Fill,fillcolor={[hsb]{\nH,1,1}},ReverseColors](-5,-5)(5,5)}
\end{pspicture}

\begin{pspicture}(-5,-5)(5,5)
% Julien Royer
% https://www.math.univ-toulouse.fr/~jroyer/TD/2015-16-L2PS/L2PS-poly.pdf
\psframe(-5,-5)(5,5)
\multido{\n=-2.0+.2,\nH=0.0+0.05}{20}{
\psContourPlot[unit=1,a=0.05,algebraic,function=sin(x)-sin(y)-\n,linecolor={[hsb]{\nH,1,1}}](-5,-5)(5,5)}
\end{pspicture}

\begin{pspicture}(-5,-5)(5,5)
% https://www.math.univ-toulouse.fr/~jroyer/TD/2015-16-L2PS/L2PS-poly.pdf
\psframe(-5,-5)(5,5)
\multido{\n=-1.00+.05,\nH=0.0+0.04}{25}{
\psContourPlot[unit=2,a=0.05,algebraic,function=(x^2-2*y^2)*Euler^(-2*x^2-y^2)-\n,linecolor={[hsb]{\nH,1,1}}](-2.5,-2.5)(2.5,2.5)}
\end{pspicture}

\begin{pspicture}(-5,-5)(5,5)
\psframe(-5,-5)(5,5)
\psset{viewpoint=50 40 20 rtp2xyz,Decran=70,lightsrc=50 30 35 rtp2xyz}
\psSurface[
    fillcolor=white,algebraic,
    intersectionplan={[0 0 1 -0.1] [0 0 1 0.3] [0 0 1 0.2]},
    intersectioncolor=(bleu) (red) (green),
    intersectionlinewidth=1,
    intersectiontype=0,
    ngrid=.1 .1,incolor=yellow!50,linewidth=0.01](-2.5,-2.5)(2.5,2.5){2*(x^2-2*y^2)*Euler^(-2*x^2-y^2)}
\end{pspicture}
\end{document}