I left the angle that was on the ends of my boards at the top and then cut the lower ends straight across.
The bottom piece fits into a rabbet at the lower edge of the back piece.
I have routed out a circular area, about half the thickness of the wood which allows a mason jar to sit into it.
Posting at the following blog parties:
My Repurposed Life
Funky Junk Interiors
Too Much Time on my Hands
Cedar Hill Ranch