Shapeoko 3 Sharpie Adapter

What a world I live in that it's easier to model and 3D print a solution than it is to find a suitable rubber band.

I wanted to play around with my newly assembled Shapeoko 3, but I'm not set up to run with my router yet. I wanted a way to attach an Ultra-Fine Sharpie (also works well with a Bic Mark-It), so I could make my machine draw satisfyingly precise smileys, letters, CAD drawings, etc.
This was a prototype to test, but it worked with minimal finishing.

Video: https://www.youtube.