%@AUTEUR: Juergen Gilg
% \section*{Twister \dots}
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	Decran=40,lightsrc=15 5 10}
\begin{pspicture}(-6,-11)(-6,7)
\rput(0,0){
\defFunction[algebraic]{klein}(u,v){u*cos(v)}%
{Euler^(-u*u)*(sin(2*pi*u) - u*cos(3*v))}%
{u*sin(v)}
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    base=0 2 0 pi 2 mul,
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    fillcolor=green,
    ngrid=50,
    RotY=225,
    RotX=-90,
    function=klein]%
}
\end{pspicture}