the pedal curve is the first in a series of curves "c", "c", "c", etc., where "c" is the pedal of "c", "c" is the pedal of "c", and so on. in this scheme, "c" is known as the "first positive pedal" of "c", "c" is the "second positive pedal" of "c", and so on. going the other direction, "c" is the "first negative pedal" of "c", the "second negative pedal" of "c", etc.