
\psset{plotpoints=1001}
\def\Lissa{t dup 2 mul cos 3.5 mul exch 6 mul sin 3.5 mul}
\def\DerivLissa{t dup 2 mul sin -7 mul exch 6 mul cos 21 mul}
\begin{pspicture}(-4,-4)(4,4)%\psgrid
\parametricplot{0}{180}{\Lissa}
%\multido{\n=2+2}{90}{\parametricplotput{\n}{\Lissa}{\pstGeonode[PointName=M_{\n}]{M_\n}}}
\psset{Derive=\DerivLissa, linecolor=magenta, arrows=<->}
%\parametricplottangent{88}{2}{\Lissa}
\multido{\n=2+10}{18}{\parametricplottangent{\n}{2}{\Lissa}}
\end{pspicture}