Maverick artist David Shrigley has come up with another clever concept, this time involving a few thousand tennis balls and joe public. Visitors to Stephen Friedman Gallery in London are invited to bring an old ball to swap with a new one from the numerous neon shelves that line the walls for Shrigley’s latest conceptual experiment, Mayfair Tennis Ball Exchange (until 8 January 2022). As more and more balls are replaced with used equivalents, the installation is transformed as the rows fill up with scruffier examples (the used balls, covered with words such as Pig and torn in half, are slowly filling up the space). Shrigley explains what motivated the eye-popping piece, saying: “My dog likes tennis balls. I throw them and she chases them. [Her interest is] more about exchange than possession.” Contributors on social media are loving the idea. “I love the idea of watching the colour along the wall shift as all of the dog-mauled balls come in,” says one happy punter on Instagram. Participants are also rewarded with a pin badge decorated in Shrigley’s distinctive handwriting. Game, set and match all round.