"Can you tell me what progress is?"

This is a question you may be asked by a young girl at the exhibition hall of Ullens Center for Contemporary Art in Beijing. If you give an answer, you may find yourself being approached by other people until you realize you are speaking with an elderly performer, having traveled through zigzagging laneways. You have actually become part of UCCA's latest exhibition by British-German artist Tino Sehgal.

The exhibition is the artist's largest presentation in Asia to date, and according to Biljana Ciric, a Shanghai-based independent curator, the show only occurs in the moment a conversation happens between volunteers working for the artist - Sehgal calls them "interpreters" - and the visitors.