There's only one STL. Print two copies normally and two addition copies mirrored in your slicer.
Takes up a 3x5 slot area. Corners can be stacked when not in use and they are tall enough to help support adjacent modules. Uses dramatically less filament than full 3x5 base designs.
Remix of Zach Freedman's gridfinity Fusion360 template.
The author marked this model as their own original creation.