A doorbell isn’t all that fancy or interesting. But there’s the contrast of the black with the red. And the stepping of the bricks leading to someone walking by. We usually imagine doorbells as being next to the door. Placed so that you’re facing the door. But this one is off to the side. So it draws your attention away from where you’re wanting to go.
This particular doorbell is on the building occupied by Pyramid Atlantic when they were in Silver Spring. At the time of this post, the building was unoccupied.