Stackable Rotate Lock 3DS Cartridge Case

I've been searching for a good design of printable 3DS casing, but it was not fruitful, so I decided to make my own, that satisfy my needs. 

Some things that I decide to have are: Stackable, Lock in place, small and thin. 

Some design have some of the features already, but I am not that satisfied, so.. as a small project, I try making it myself. 

First I was thinking of making a hole with a small clearance fit, but for an extended period of time, that is not a good idea because of the friction will cause some abrasion (?) (sorry my bad english). 

So I think of this as my second idea, and it works well (yay!)

So please remix this or update this design to make it more material-friendly, higher asthetic value, or just as weird as you can be. :D Best Grüsse!