I was trying to re-create the box made in this video:
But then realized I didn't have the same end mill and had to make a few adjustments. Either way I'm super happy with the results.
Here's a plug for my rabbeted box generator, which creates Carbide Create files for boxes with dimensions you supply. It'll get you 5 out of the 6 sides you need, and you can add in the channel and the lid from there.