how to cut this corner lap joint on 2x4s ?
Its embarrassing to even ask this to a group that probably think this is Lincoln log childs play.

I guess the "proper" thing to do is get a nice Dado blade set- but lets say that I want to get a little more creative. How does one make this top cut without standing an 8ft pressure treated 2x4 on its end?

Im trying to think outside the box- is there some jig or adjustment this rookie can make to keep from having the blade cuts run/extend/drag past the cut out area on the 2x4 ?

The wife wants some raised bed box gardens. But Im trying to think of a creative joint that would be simple, strong and easy to replicate on a hundred boards.

LIke this:Box garden joints.jpg