Curve traced by a line as it slides along another curve about a fixed point
Conchoids of line with common center.
Fixed point O
Given curve
Each pair of coloured curves is length d from the intersection with the line that a ray through O makes.
d > distance of O from the line
d = distance of O from the line
d < distance of O from the line
Conchoid of Nicomedes drawn by an apparatus illustrated in Eutocius' Commentaries on the works of Archimedes
In geometry, a conchoid is a curve derived from a fixed point O, another curve, and a length d. It was invented by the ancient Greek mathematician Nicomedes.[1]