Sand Drawing machine

I'm building a sand-drawing machine. I am using the basic structure of hypercube.

I'm using the original pieces of the thing https://www.thingiverse.com/thing:1752766, but I needed to adapt the piece to the 8mm axes.

I designed a piece that holds a 20mm diameter cylindrical magnet, which goes in place of the hotend of the original 3D printer hypercube.

Arduino Uno witg GRBL 1.01
CNC Shield

This video shows the machine drawing a set of nested kock fractals.
https://youtu.be/bzk1mmtbSzo