Im still stuck with this script and deadline is coming 
that is the last bit left to solve, anyway 
Since my problem is to understand and use the new plane (there is something about planes Iam still confused) I cannot create the other box from mid point to down, in order to create the slits of the waffle. (I picked the points, even a reference line, but the angle and plane are a problem for me).
TEST2.gh (39.7 KB)Hope someone can give me any advice again
I used a different plane as the basis for the box, the original SFrames flipped, then replaced your center box with a domain box.
I spent some time four years ago playing with this problem of notching intersecting “rafters” on a waffle roof:
OOPS! I see now this is a duplicate thread and I don’t have the full context without reading the first one, what came before. 
Using Divide Domain to get two boxes in place of one:
No need to double post.
Waffle - Extruding geometry along a curve doesn't fit
Thank you! that was easier and more convenient to use the domain box and know exactly what component is necessary 
ps. I am new here and wasn’t sure if the post would refresh for everyone only commenting on it, sorry to double it. @Fred_C
