Thank you for pointing out this typo in the tutorial. An updated version will be published promptly.
To make it a bit easier to set up the Z-shaped ribbons, I have also developed a new script which completely eliminate all complicated steps in VNL. I will publish it on the Forum very soon.
However, the tutorial as it is serves as a nice demonstration of how to make the various tools in VNL work together to set up complex geometries in the case when you don't have a ready "geometry generator script". Often, performing the steps by hand in VNL is the first step when you develop such a script anyway!