creating bent strip module

Hello. Here's a strip module I'm trying to create in gh.

In reality it's very easy to construct: two identical strips "intertwined" to form one unit (first picture). Only rule is that the mid-points of their edges meet. 

In GH, I tried to set the parameters for middle curve (pink curves in ModulePic1.jpg), and then extrude the curve w/ curve frame. Second picture below is the result I have so far.

Obviously it's is not working out in many ways, mainly because the direction of extrusion shouldn't be a single x,y or z vector. Also, the setup for the initial curve isn't ideal either. I'm not sure how to fix either. Attached is the definition. 

Does anyone know any ways to make the module look like in picture1? This doesn't sound complex but I'm very new to GH.

Many thanks in advance!