I made a small box out of Foamalux the other day and printed a seat belt & no smoking sign.

The decals are printed on “overheads”. At least that is what we used to call that transparent film that teachers uses to use before Power Point was invented. Two layers prevents the light from shining too much through on the black parts.

On the back side if the box there are 2×5 yellow LED in each section. and I am interfacing it to Prosim later today using the gates. There are no direct indicators for these two functions, but there are gates that I then can trigger the LEDs with.