Dubbed the "Space Waffle" by some of its residents, the striking grid system that Steven Holl employs for the design derives from his concept of "porosity," and while it appears massive in scale, the depth of the windows does give it a sense of permeability. The 18 inch deep windows blocks the summer sun, but also allows Holl to play with color, with each panel in the recess colored different. The exterior, while very regimented in its design, actually serves as a framework for an organic interior. Long amoeba-shaped internal cavities slice through gridded structure bringing light into the central core. The also serve as the "lungs" of the building, drawing warmer air upwards in order to cool the building down.