1
You'll need a bit of glue to secure the spikes.

2
Before you print the whole thing, do a quick test print to check how the parts fit together. It should only take about 5 minutes. I've included a file called JointTest for this.

3
If you need to tweak anything after the test, you can use a 3D editing program like Fusion_360. The file is attached.

Four rows of holes in different sizes mean you can store lots of stuff, like paintbrushes, pencils, pens, knitting needles, and more. 13mm, 10mm, 10mm, 6mm.
 

Enjoy! 😊