Snappy Expo / Dry erase marker holder

I didn't like any of the existing expo marker holders and my dry erase board in my office isn't magnetic so I needed something that could clip onto the tray.

**Features**:
       ✓ Prints flat with no support
       ✓ Uses minimal material
       ✓ Markers can be stored cap up or cap down
       ✓ Markers can snap in place
       ✓ Configurable for different size markers
       ✓ No glue required for assembly
       ✓ Source shared for others to remix
![Expo snap demo gif](https://i.i