Slovak artist Jurak Kralik convinced tennis star Martina Navratilova to spend four years hitting paint-covered tennis balls against 60 large canvases in a practice she calls 'tennising'. The colourful results are now on show in Art Grand Slam at Roland-Garros, home of the French Open
Wed 28 May 2008 07.59 EDT First published on Wed 28 May 2008 07.59 EDT