Cube made from 3 identical pieces. "Trisection of a cube" or "Helicoid Cube"

I saw this on youtube
https://www.youtube.com/watch?v=fD-zIUYhHps
and thought it would be a good challenge to try and figure out how it works and try and model it in SolidWorks. It took me a while to figure out but I finally sorted it out.
I haven't printed this yet as I'm waiting for a replacement print bed to arrive. I don't anticipate any issues though so it should be safe to print.
3 of these will make a 4 inch cube which is quite large, you might want to scale it down before print