Stream gate or general help

Hello, I’m trying to have a joinery drawing done. I’m stuck. I’m drawing the frame, but if I add a mullion in the middle, I want to draw the slat that way. I looked online but didn’t understand the stream gate. What I want to do is draw a rectangle, then draw the slat profile. If I draw a line in the middle, I’ll add the mullion line where I drew it. I want to adjust the slat profile accordingly. How can I do this? Or what research should I do?

dograma.gh (11.4 KB)

dograma.3dm (43.2 KB)

I did this in a few tries. I think it worked, what do you think?

dograma.3dm (43.1 KB)

dograma.gh (20.8 KB)