Driving home a couple of weeks ago and saw Martin Creed's installation on the front of Tate Britain. It cheered me up (difficult week) and it was so unexpected. I'm guessing there's a level of irony in it but I found it strangely calming and comforting in the circumstances. The combination of simplicity and message is at the heart of Creed's neon works - they call a spade a spade. I like the straightfowardness of these works. Art has many functions - amongst others - to challenge, to reassure or disconcert but above all, to communicate.