Georges Perec, Life A User’s Manual

As each puzzle was finished, the seascape would be “retexturised” so that it could be removed from its backing, returned to the place where it had been painted — twenty years before — and dipped in a detergent solution whence would emerge a clean and unmarked sheet of Whatman paper. Thus, no trace would remain of an operation which would have been, throughout a period of fifty years, the sole motivation and unique activity of its author.