This design is free to use. It's intended for 1/8 inch thick material, and the completed assembly stands at about 10.1 inches tall. There is a CAD mockup of the design available as well, although it is missing some truss cuts.
Each side, as well as the top, has a hole which is wide enough for a lego axle to easily fit through. There is an option for the bottom section of the sides to be full holes or truss cuts, as well as for the top to have tabs instead of tab inserts (find an svg editor such as inkscape to unhide the layers). By default, the mirrored sides have truss cuts and the unmirrored sides have full holes to differentiate between the two easier.
The parts needed for the assembly (should all fit on a single GlowForge sheet):
- x1 top
- x1 bottom
- x3 side
- x3 mirrored side
When assembling, alternate between placing mirrored and unmirrored sides; the intention is to have the truss holes line up with each other on opposite sides.