Ai Weiwei, Modern Toss, The Turner Prize: this week’s new exhibitions
From Ai Weiwei’s show at Blenheim Palace to The Turner Prize in London, Skye Sherwin and Robert Clark find out what’s happening in art around the country
Lygia Clark
Radical geometry: South America’s surprising art
All eyes are on Brazil’s World Cup but a new Royal Academy exhibition showcases a different kind of South American artistry, and makes a stunning case for the continent’s geometric art