I picked up a set of Uni Posca paint pens while working on a project. They came in several boxes and, I quickly realized they would be a lot more pleasant to use if I had a way to keep them organized. There are a bunch of appropriate caddy designs floating around that use planes with aligned holes. While those use less acrylic, they seem kind of fiddly to insert and remove pens. In the interest of keeping friction while working to a minimum, I designed this divided box caddy. This works well both upright and on horizontally.
I remember my grandmother working with acrylic in the 70s. I think she would have been amazed at how quick and easy this sort of thing is now with digital fabrication. Solvent bonding the pieces still requires some dexterity and practice to master but, doing precise layout in Inkscape and having the laser cut the pieces perfectly would have been magic back then.