Celebrated American painter Cy Twombly, whose paintings featured scribbles, graffiti and unusual materials and who invigorated American post-War art alongside Jasper Johns and Robert Rauschenberg, has died. He was 83.

Internationally known Chinese artist Ai Weiwei was released from prison last week after a three month detention. Jeffrey Brown gets an update on Ai's situation from Alison Klayman, who has been working on a documentary about him, "Ai Weiwei: Never…