I watch a lot of YouTube woodturning videos. I also watch videos on CNC woodworking machines. So, YouTube decided to recommend a video that combines the two subjects. The linked video is the first in a series of three that show how you can turn a rope twist pen on a CNC machine. The video is from a class Legacy Woodworking Machinery (a maker of CNC machines) provides its owners.
In addition to showing how to make a rope twist, they also show how to make a pen that has a gentle curve to it. Interesting, but I don't think I'll be throwing away my lathe.
Note: One of the disappointing things about the video is that it doesn't show any actual wood being cut. It just shows how you would program the machine.