All three artists rupture the boundaries of their media and explore uncharted frontiers. Steve McQueen's films and videos at the ICA (closed March 21) resemble music more than any other art form- but strangely enough, most of them are silent. German artist Andreas Gursky's recent works at the Serpentine (closed March 7) take the filmic canvas in new directions. In a work that nods to both minimalism and suprematist experiments with form and colour, he photographs Jackson Pollock's One: Number 31 in an empty gallery whose walls complement the beige tones of the canvas. Patrick Caulfield's recent works at the Hayward Gallery (closed April 11) gave me the impression that the world is made up of hundreds of different alphabets and that Caulfield has chosen just one alphabet and decided to depict the world in this singular language.