There are two lights outside the building, one to shine in through the downstairs windows, and another for the upstairs windows. A typical setting of brightness equivalent to 88 watts was found to produce a nice pleasant lighting where shadows cast by the window frame creates an illusion of sunlight to make the environment seem brighter than it really is. Additionally, because the light comes from outside the building, the reflections in the windows produce a feeling of duplicity, and, because of the 45 degree angle between the windows, also a feeling of quadplicity. Thus the outdoor light source gives the space a large open bright feeling with only a minimal consumption of electricity.
(the downstairs space)
The "natural artifical light" effect allows a very small amount of light (lights dimmed down low) to creates an illusion of bright sunlight inside the building. The shadows cast by the window frame create the visual impression of more light than there really is. In this way electricity is saved and energy consumption is reduced.