The simplest of the machines functions is a plotter,graphics drawing application. I made the holder so it fits sharpie markers which are widely available and used frequently by lots of folks in making.. The pen holder is adjusted so just the weight of the marker itself provides ample pressure for drawing.
The colors for sharpie seem endless!
This attachment consists of two 3 D printed parts fused together. It bolts on the Z axis like the others using the two wingnuts.
I often use this before laser or routing on a piece of scrap paper to check the tool paths and make sure everything is a go.