The conchoid of Nicomedes is an algebraic curve of degree 4 that was studied by the Greek mathematician Nicomedes already in the 3rd century BC. He probably used the curve to solve two well-known geometric problems, namely the doubling of a cube (Delian problem) and the trisection of an angle. We know today that neither of these problems can be solved by a ruler-and-compass construction.
Given a point (origin of the coordinate system), a line (directrix, parallel to the y-axis) and a circle radius. This radius can be adjusted using the slider on the panel. For each line passing the origin, let M be the intersection of this line and the directrix. A circle with the given radius is drawn around M. All points obtained by intersecting the line through the origin with the circle form the conchoid. The name "conchoid" means "mussel curve" and refers to the shape of the curve.