Poinsot's Spirals

$\begin{figure}\begin{center}\BoxedEPSF{poinsots_spiral_1.epsf scaled 500}\end{center}\end{figure}$

$\begin{displaymath} r\sinh (n\theta)=a. \end{displaymath}$

$\begin{figure}\begin{center}\BoxedEPSF{poinsots_spiral_2.epsf scaled 700}\end{center}\end{figure}$

$\begin{displaymath} r\mathop{\rm csch}\nolimits (n\theta)=a. \end{displaymath}$

References

Lawrence, J. D. A Catalog of Special Plane Curves. New York: Dover, pp. 192 and 194, 1972.