Most art galleries and museums have a strict policy regarding the touching of artworks by visitors. They usually put up simple orders that say DON’T TOUCH or more desperate petitions of PLEASE DON’T TOUCH. My work TOUCH WOOD is the simple word ‘touch’ made as large as possible, to be placed larger than life, inescapably, on the floor of a gallery.
The idiom ‘touch wood’ is usually expressed when one wishes something bad not to happen, but it is believed to be equally effective if one wishes for something good to occur. Murphy’s law states that if anything can go wrong, it will. This law has a degree of underlying superstition and so does ‘touch wood’, when uttered to revoke Murphy.