No one would want to pay a penny for an empty canvas by me. But it would be quite another if the empty canvas were signed by a great artist. I would be surprised if an empty canvas by Picasso or Matisse signed and inscribed with the words, 'I wanted to paint such and such on this canvas, but did not do so,' would not fetch thousands... After all, with an empty canvas, the possibilities are limitless, and so perhaps is the cash.