This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/3rz7QjizSzf

I needed a modular approach to display my ever growing pin collection and baseball cards.
Completely modular so you can print more pieces and add to each row and column. start with the four corners, you will need 2 left and 2 right. The 2 left will be in diagonal corners, duh. The middle insert is a spacer for the back of the pins. If you are a collector you'll know what I'm talking about. If you want to display baseball cards you won't need the inserts but it's a nice way to protect the edges.

Feel free to resize for your own needs but please post pictures and likes!