Liu Bolin, better known as the Invisible Man, is famous for his work in "camouflage," painting himself to blend in with the background.  In his performance piece Winter Solstice, Liu comments on the pollution issues surrounding China.  He paints a troupe of dancers to blend in with a dying forest and smog-covered Tiananmen Square, calling attention to the drab palette he used to accurately camouflage his subjects.  Then, the dancers laid down and rolled up and down on the ground, struggling against the winter smog.