The values of e (eccentricity) and d(distance of directrix from nearest focus [the one at the origin in polar] are adjustable via the sliders lower part of the left window[br][br]The value of q ([math]\pm1[/math]) changes the location of the directrix from + to - side of the origin and can be set with the slider at the bottom of the left window.[br][br]P is a point on the conic curve and can be moved along it by dragging the point itself.