Secret hole Clock / Secret hole Clock

Let's suppose that you drive a nail on the wall to hang a clock on it.
Usually, the wall clock has a small hole in the back to be hanged on the wall through a nail, but it's not easy to put it on the wall, because you cannot find the small hole easily.
With this clock, you can easily find the hole to hang it on the wall in front of you, when you sightly turn a small object indicating 12 o'clock.
If you spin the object into the original location, the space that had a hole disappears completely and you can see the clock, which is neat and refined.