Making signs with deeply-engraved letters

This amusing Do Not Disturb sign was adapted from a humorous sign in the animated TV series Moral Orel.  A Thingiverse user shared the design in several formats so it could be built using a laser cutter, robo cutter, or 3D printer.

I built it on the SD300 by starting with ivory/white material for most of the build and then substituting red material for the last layer.  That resulted in neat, sharply-defined letters in deep relief.

I liked the joke so I took it a step further, designing a door hanger and sharing it as a derivative design.  I flattened the design a little, but kept some depth because the relief makes the graphics look attractive.