OK, you’ve missed this. The show came and went, all too brief. As the name suggests, it happened in Mayfair, London, at the Stephen Friedman Gallery where the creator behind the project, David Shrigley, is one of a storied roster of artists. It was such a neat idea we can only imagine it is likely to pop up in a gallery or institution in another city somewhere in the world soon. As the pictures indicate, the gallery was full of tennis balls. “If you need tennis balls, we’ve got them all here,” said Shrigley of the installation when he looked around rooms clad in a total of c. 12000 balls. The visual impact was not the main point, even though there was a kind of Op Art impact to the massed balls. The concept was that there was an open invitation to visitors to come along with more tennis balls and exchange them freely with the immaculate specially made (unbranded) ones on the shelf. They could bring branded new ones or could bring manky, half-rotten balls rescued from a damp corner. Whatever, as long as it was a tennis ball. They did not only get a ball back but also a badge as a token for their taking part in the trade, in the exchange. Shrigley was in part inspired by seeing how his dog would fetch and respond to tennis balls, give it up or defend it, endlessly fascinated by this interaction on a daily basis. Shrigley liked the mildly subversive act of doing this as a free exchange in Mayfair, where trade is typically a much more expensive activity. But we could imagine a shop doing something similar, briefly, as a product launch, as a pop up, a very limited release, a priceless offering.