No glue or screws, I just made cuts about halfway down on each piece where they intersect so that they slot into each other. Since the cuts were imprecise, I used a chisel to take off material until it fit nicely.
There are the 5 pieces going vertically, slotting into the one horizontal one each at the top and bottom. It’s easiest if you clamp all the identical pieces together when you make the cuts and fine adjustments, that way you don’t have to cut every piece individually. :)
That’s an interesting idea, I like it! I hope I remember this if I ever have to make another one!