Conchoid

[Sarah]

A curve, of the fourth degree, first made use of by the Greekgeometer, Nicomedes, who invented it for the purpose of trisecting anangle and duplicating the cube.

[Greta]

A plane quartic curve consisting of two separate branches either side of and asymptotic to a central straight line (the asymptote), such that if a line is drawn from a fixed point (the pole) to intersect both branches, the part of the line falling between the two branches is of constant length and is exactly bisected by the asymptote.