%@AUTEUR: Juergen Gilg
% \section*{Twister \dots}
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\defFunction[algebraic]{twister}(u,v){cos(u)*(4*sqrt(1-v^2)*sin(abs(u))^abs(u))}%
{v}%
{sin(u)*(4*sqrt(1-v^2)*sin(abs(u))^abs(u))}
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    RotZ=90,
    function=twister]%
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