First, in constructing the building, 75% of the building materials were recycled materials. Furthermore, at least half of all the building materials came from nearby ( less than 500 miles aways) to use less energy in transporting them. Now, special mirrors on the roof bring the sunlight into the center of the building so that most of the employees can work under natural light. The windows in the building can be opened-unlike windows in many American office buildings-so that people can get fresh air. Indoor gardens make the place more pleasant and also help clean the air of pollutants. Above all, the energy use has reduced by 43% and 32%, compared with other buildings of same size.