\documentclass[12pt]{article}
\usepackage{pst-3dplot}
\begin{document}

\psset{unit=3cm,Beta=10,Alpha=60}

\begin{pspicture}(-1,-1)(1,1)
\pstThreeDCoor[xMax=2.5,yMax=2.5,zMax=2.5,drawing=false]
\pstThreeDBox(1,1,-1)(-2,0,0)(0,-2,0)(0,0,2)
\psplotThreeD[linecolor=blue,drawStyle=xyLines](-1,1)(-1,1){x 2 exp y mul}
\psplotThreeD[linecolor=red,drawStyle=yLines](-1,1)(-1,1){x 2 exp y mul}
\end{pspicture}

\end{document}
