This is a Litho Box I based off my other litho box without the need of a topper. Less parts to print, simplified, and less print time. Still has the cord relief for ease of use as well.
 

Added an additional "Flat Roof" for easier printing and less material. Flat roof is thinner and does not have the angle on top so you can print from either side.

Pictures: 

127mm X 127 mm

4mm max thickness

Picture site: https://lithophanemaker.com/Framed%20Lithophane.html

Light Recommendation: https://www.amazon.com/dp/B0B28NX924?ref=ppx_yo2ov_dt_b_product_details&th=1

Other light box with topper: https://www.printables.com/model/836887-litho-box-5-x-5