public override List <Point3D> DropPointsOnPerimeter(double dl)
{
List <Point3D> R = new List <Point3D>();
Point3D A = new Point3D(Position.X - Radius, Position.Y, 0);
Point3D B = new Point3D(Position.X + Radius, Position.Y, 0);
Point3D C = new Point3D(Position.X, Position.Y + Height, 0);
R.AddRange(Figure.PointsOnLine(A, B, dl));
R.AddRange(Figure.PointsOnLine(B, C, dl));
R.AddRange(Figure.PointsOnLine(C, A, dl));
return(R);
}