% Eight petal rose: r = cos(4t)
\SCALEVARIABLEfunction{4}{\COSfunction}
                      {\ffunction}
\POLARfunction{\ffunction}{\rose}
\begin{center}
\def\runitdivisions{3}
\MULTIPLY{2}{\numberTWOPI}{\numberFOURPI}
\setlength{\unitlength}{2.5cm}

\begin{Picture}(-1.5,-1.5)(1.5,1.5)
\polargrid{1}{16}
\pictcolor{red}\linethickness{1pt}
\PlotParametricFunction[16]\rose{0}{\numberTWOPI}
\end{Picture}
$\rho=\cos 4\phi$
\end{center}
