Four Tibetans feature among the portraits of 176 political prisoners from around the world who are depicted in the latest exhibition by Ai WeiWei, the Chinese dissident artist. His installation Trace is currently on show at Smithsonian’s Hirshhorn Museum and Sculpture Garden in Washington in America and is made from thousands of Lego bricks. The four Tibetans featured are the Panchen Lama, Tashi Rabten (Theurang), Lo Lo, and Jigme Gyatso.