How to Write Dog-bones

When cutting wood with CNC, square holes can not be drilled with an end mill. Therefore, it is necessary to cut the corner of the square hole a little larger. I wrote this technology using SketchUp. Maybe I can't draw it any more easily. If you have a way to write, please let me know.

The operation is published in the video.
https://www.youtube.com/watch?v=1DzobjPoa0A

The plug-in used is CleanUp3.
https://extensions.sketchup.com/en/content/cleanup³