Most information on conchoids I have been able to find deal with a straight line (conchoid of Nicomedes). What work has been done on or using other types of conchoids? Are they used in any applications or other branches of mathematics? So far, I haven't been able to find anything. Any books or articles I should read?
Additionally, what are their most interesting or surprising properties?
For clarity, the line/curve I'm talking about is what one endpoint of a segment follows as its other endpoint traces the conchoid itself provided that the segment always passes through a given fixed point.