In mathematics, Poinsot's spirals are two spirals represented by the polar equations
where csch is the hyperbolic cosecant, and sech is the hyperbolic secant. They are named after the French mathematician Louis Poinsot.
Examples of the two types of Poinsot's spirals
The Poinsot spiral r=csch(θ/3).
The Poinsot spiral r=sech(θ/3).