\documentclass{article} \usepackage{pst-plot} \begin{document} \newcommand{\rau}{2 t mul cos 3 mul sqrt} \psset{unit=2cm} \begin{pspicture}(-3,-3)(3,3) \parametricplot{-45}{45}{\rau\space dup t cos mul exch t sin mul} \parametricplot{-45}{45}{\rau\space neg dup t cos mul exch t sin mul} \end{pspicture} \end{document}