This is a bigger version of my original Mini Shelf.

I wanted something that I could expand without making new holes, and no visible screws!

The hook has 3 holes, you can use it like this:

Combine it with the Mini Shelf. Check my profile or use the link here:

https://makerworld.com/en/models/446662

With the adapters, they can be locked together:

The video below is of the Mini Shelf, the locking and hooking system is the same.