Nice, to be sincere, after looking at it, this was the only thing that came to my mind. However, I thought you had filled the "holes" with a dark color so we couldn't guess which plugs they were.
Looking at the original image, now I see that I was completely wrong :)
Thanks this was fun.
just an idea, it would be cool if all images are related to Bitcoin or Blockchain somehow. And that would give us a common first hint too, because with the first hints you give it is very hard to guess😃