Carmine, thank you for writing. This is actually fixed windows to the exterior. It is frosted glass for privacy and this shot was taken at dusk. In the day light, this bath is flooded in a very soft wash of light. The frame of the windows is behind the mirror, just below the counter top and above the ceiling plane to have a crisp line. The finish materials come right up to the glass with about a 1/8" gap to allow the window to expand.

The cool trick here is that the walls of the house are behind the mirror, so the depth of the side of the mirror is the depth of the exterior wall. This allowed the deep recess in between the mirrors for decorative items and not take up the usable counter space. Notice there is a can light at each recess.

I wanted to use flood lights outside to back light the glass, but having the side of one's house lit up that bright was not going to happen...

Also you are right that it does look like a blue wall with semi gloss paint...