As he planned his latest exhibition, to be shown at Australia’s National Gallery of Victoria this year, Chinese artist Ai Weiwei placed a bulk order for plastic bricks from Lego. The Danish company denied the dissident’s request, citing a policy against “the use of Legos for political works.” Now, brick by brick, Ai is shaming the toy maker on social media.

Over the past few days, Ai has shared dozens of portraits of political detainees, built from Lego bricks and then digitally rendered, that originally appeared as part of his 2014 show “Trace” at the former prison at Alcatraz. They include Nobel laureate Aung San Suu Kyi, who leads the opposition pro-democracy party in Myanmar, and Saudi citizen Shaker Aamer, who was detained by the U.S. at the military prison at Guantánamo Bay for 13 years without charges and recently was returned to the U.K.

So far, 43 portraits have appeared on the Instagram account, with Ai saying he will post 10 images a day for 18 days to protest Lego’s “act of censorship and discrimination.”

Below are just a few of the portraits. You can see the rest on Ai Weiwei’s Instagram page.

Correction: Several Ai portraits of political prisoners appeared at a 2014 exhibition on Alcatraz Island. A previous version of this report incorrectly stated the works posted on social media were new.