I started with the excellent design by brimstone326. I wanted a closed design, rather than the tap light version. So I added a tube to the base to allow wrapping an LED strip, which illuminates the different panes. There is a small hole in the base to pass the strip and wire through.

The viewing panes are 156mm x 104mm x 2mm.

An excellent site for making Lithophanes: https://3dp.rocks/lithophane/

An excellent tutorial: https://www.instructables.com/How-to-3D-Print-a-Photo-Lithophanes-101/