Wikipedia
Cochleoid
A cochleoid is a snail-shaped curve similar to a strophoid which can be represented by the polar equation
$$r=\frac{a \sin \theta}{\theta}$$
the Cartesian equation
$$(x^2+y^2)\arctan\frac{y}{x}=ay$$
or the parametric equations
$$x=\frac{a\sin t\cos t}{t}$$
, $y=\frac{a\sin^2 t}{t}$ .