Bookshelf Backstop Adapter

I modified the original design to add a connector and slot so the units can be connected together. I printed it with the front face down to make printing the connector and slot cleaner.

These are the rough dimensions of the finished project:
Height: 4 inches
Width: 6.1 inches
Depth: 4.5 inches

Designed in TinkerCAD

3D Printer used: FlashForge Adventurer 5M Pro, 0.4 mm nozzle
Filament: OVV3D Rainbow PLA Filament 1.75mm
Infill: 10%