On Great George Street someone has covered the outside of a derelict tenement block with old front doors, all painted red. This is good public art because nowhere does it explain itself: the only sign anywhere on the doors is an old one saying BEWARE GUARD DOGS. It's left to the inquisitive passer-by to investigate and ruminate (and occasionally it seems, around the back of the house, urinate) on it. So: a source of curiosity and inspiration but also (and this is also a mark of the best public art, I think), its really good fun!