Ai Weiwei:Trace at the Hirshhorn is an exhibit about freedom and repression. It features 176 portraits of political prisoners and human rights advocates from thirty countries. More than a million Lego bricks were used to construct the portraits. The portraits are pixelated, similar to the pixelation of low-quality surveillance images.
The exhibit was originally designed for a show at Alcatraz in 2014. For the Hirshhorn exhibit, Ai Weiwei designed new wallpaper, called The Plain Version of the Animal That Looks Like a Llama but Is Really an Alpaca. The wallpaper has drawings of security cameras, handcuffs, and the Twitter logo for the tweets that Ai Weiwei has used to communicate with the world, plus llamas.