The above device is essentially a box containing a mirror angled at 45 degrees, so when you look into it you only see what is above you. The idea behind this was that the viewer would position themselves in a narrow space on the site (a lane, an alley, etc.) and look through. They would see the tops of the buildings on either side of the framed view, as well as a piece of the sky in between. This would, in turn, create an awareness or sense of the void, the piece of sky you normally wouldn't focus on. The inspiration for this idea came from the photographic series of building tops from Assignment Two, as well as the interior mechanisms of certain cameras (see below):

 

The device then took on a new form with the same concept of angled mirrors, only another mirror was added in the opposite direction. This change allows one eye to see straight up while the other sees the ground- the intention being to walk with the device as you are looking at these two images being overlapped and in a sense merged into one by your brain.