Here is a square box with a plain lid. Set the box height at 9 inches and the lid at 7.1 inches to cut a 3×3″ box. The layered files have a layer for scoring with solid lines. The files without “layer” in the name do not have score lines.
The download includes layered svg files for use with SCAL 2.0 and single layer svg files for use with SCAL 1.0. These files are for personal use only. Feel free to link to this post, but the files are not to be shared or distributed in any way.
Download the files from here.