Parallel Line Shadows

So I am trying to get a handle on parallel lines shading with Pen display mode. So currently I have the shadows set to a green color so I could see what is being generated by “Shadows” My question is why isn’t the shading on the box Parallel lines, it just solid color shade? How do I set the shading/shadows on objects to parallel lines?

Have a look at the “Patent” drawing mode on this page:
http://wiki.mcneel.com/rhino/advanceddisplay