Courbe(s) paramétrique(s)

$$$ \forall\alpha\in\{0,2\pi\}\quad\; k_{a}\in \mathbb{N}\quad1\leqslant\;k_{a}\;\leqslant3\quad\;$$$
$$$ \left \{ \begin{array}{r c l} \theta(\alpha)& = &\cos{(\alpha)}+\pi\cdot\sin{(\alpha)} \\ r(\alpha)& = &0.24\times\cos{(k_{a}\cdot\alpha)} \end{array}\right .$$$