Thanks it solves the problem I have.
I have more questions.
I would like to ask how can I temporary display additional line of rectangle that indicates the normal of it?
By normal, I mean the line that is derived from cross-product of first two segments.
I would like to see the line while it is drawn :
And once it is drawn it would disappear:
I see that rectangle is the default Rhino method from this rhinocommon method:
Rhino.Input.RhinoGet.GetRectangle(mode, base_point, prompts)
But I cannot find any information in the primer or elsewhere how to alter the display while drawing