Inop.

I'm not sure who put these signs on the proximity card readers at work but since I first saw this, others identical to it have appeared.

Observations:

• A canvas was created. Pretty hard to write on the reader otherwise - etching or maybe silver marker pen? Only fairly permanent methods come to mind which makes the canvas logical since…
• Being out of service is probably (hopefully) a temporary state so the annotation should also be temporary.
• Some kind of tape is combined in rows to make an area to write on. More elegant than taping some paper - trickier construction but the canvas is subject to the elements and paper is pretty fragile so it may be more durable this way. Nice.
  
• Words on the canvas: CARD / READER / INOP. This is the most interesting part to me. the words "CARD / READER" are fully written out but everybody that needs to know it's broken already knows what it is. To me, the critical info is that it is broken. Interestingly, of all the words to convey "broken", the creator chose the word "inoperable" (I think) and then abbreviate it as "INOP.". Perhaps this reflects the technical term internal to his/her maintenance team? I guess the alternatives aren't that great either though: out of service, malfunction, doesn't work, etc.?
  

The sign took me almost no time to understand but I'm pretty sure I knew something was wrong with it just by virtue of it having stuff stuck on it and writing on it. Several colleagues mentioned it was confusing to them at first.

If this were a blog with high volume and active readership, I'd ask readers to design versions. I wonder what the simplest version would be? X with two strips of tape? Is anyone out there? Prototype? :-P I won't hold my breath.