I remember seeing my first Ai Weiwei installation in person. It was his collection of porcelain sunflower seeds at the Tate Modern and it was a sight to behold. It gave me my first sense of the scope and scale in which the Chinese artist works. His latest exhibition, in New York, is no less as ambitious. It’s called Good Fences Make Good Neighbours, and features site-specific works dealing with the theme of migration and people moving across borders and space. The two largest pieces of the public art showing (which also celebrates the 40th anniversary of New York’s Public Art Fund) are located in Central Park and in Washington Square Park.…