Reciprocal Self supporting frame (shift frame)

HI!
 I want to connect my anchor points like in a reciprocal frame. But grasshopper will only conect the endpoints of lines. I can't connect them from a point on a line.

 My Problem is the following. I need to connect point 1 to point 2. Then on the line between 1 and 2 is another point 6 beeing the endpoint of the line from 5 to 6. same for 3 and 4 having the point 2 on the line. But the connecting line should always stay straight. so it should not bend on the point inbetween. here a picture for understanding.

In the end I want to have a structure which looks like this:

I would be happy with any help. I'm just too bad with grasshopper and kangaroo...