Built with cedar, with the back assembled with pocket screws and glue to connect the 4 boards. After connecting, I sanded using an orbital sander with 120 grit sandpaper. The sides are 1” x 2” cedar boards with 45° corners.
For a 3D look, I put in the top of a metal garden terrace. With it, I get a nice silhouette with the back lighting of the Nanoleaf Canvas.
You can also see these pics in my 2019 DIYs in this Flickr Album.