an airplane curve with polar equation or , that the cardioid is a particular instance.

A curve associated with the fourth degree, invented by Pascal. Its polar equation is r = a cos θ + b.

Any univalve layer.

A curve, developed and known as by Pascal, generated from a circle by the addition of a constant size to all the the radii vectores attracted from a point of their circumference as an origin, using proper account of bad radii vectores.

## How would you define limaçon?