Before revision: The Negative Pedal Curve (NPC) of the Ellipse with respect to a boundary point M is a 3-cusp deltoid which is the affine image of the Steiner Curve .
After revision: The Negative Pedal Curve (NPC) of the Ellipse with respect to a boundary point M is a 3-cusp closed-curve which is the affine image of the Steiner Curve .