Chặn Kệ (Shelf Stopper) cho Cứng Cáp Hơn

I had a problem, the shelves were shaking but i solved with this model.
It cannot be usefull to many people but the model is not detailed so it's easy to remix it if you need.
I used four M4 self-tapping screws each and it's too much, you can use just 2 or 3.
Hope this can be good for some of you :)