The last day of M's exhibition 'Thunder Head and Rainbow Face' means stripping the bright, filled-in walls of the Blue Oyster back to white space.
It's saying good-bye to the paintings that were bought, now away from our gaze, leaving behind emptiness.
That's the nature of art - one-offs. Unlike the repetition of the printing press.
Or of song. As Joni Mitchell once said after someone in the audience yelled out for a song; "Funny how Vincent Van Gogh was never asked to paint us 'Starry Night' again."