AutoCAD .NET :: Draw Rectangle Using ObjectARX And SDK

I have to draw a rectangle using ObjectARX but the problem is that i cannot find a method for the task, I found all kind of other methods like Line, Circle, ..... I managed to do it like that:

Point3d pointA = new Point3d(20,20,0); Point3d pointB = new Point3d(40,20,0); Point3d pointC = new Point3d(20,10,0); Point3d pointD = new Point3d(40,10,0); Line line1 = new Line(pointA, pointB); Line line2 = new Line(pointA, pointC); Line line3 = new Line(pointB, pointD); Line line4 = new Line(pointC, pointD);

But I thnk there must be a way to do it more easily.

I am still new in ObjectARX.