Lithophanes...

A lithophane (French: lithophanie) is an etched or molded artwork in very thin translucent porcelain that can only be seen clearly when back lit with a light source.  More recently lithophanes have been made with the use of CNC  machines and 3D printing.  Watched a couple of tutorials on YouTube and thought I would give it a shot.  The software tells the printer to print the light areas in a thin layer and the darker areas progressively thicker.  57,62,33,0,C