A strap-on case for artseyio/thepaintbrush.
The gaps allow for a material less than 4 mm thick to be used for a strap.
If using a rope or shoelace to attach the palette, I've found a round turn and two half hitches for a fixed side and a clove hitch for the working end work well.
I recommend 3D printing the stl at the following settings:
PLA or similar
0.4 mm or smaller
0.2 mm or less
20% or more
On