How do you ever know when a piece of art is finished?

Poet and artist Frieda Hughes muses on one of those paintings that sits there, watching other paintings go by, until... at last… it’s completed (but is it?)

This painting was hesitant; it sat on my easel while I began / And finished other paintings, evolving slowly, puzzlingly (Frieda Hughes)

ROCKS ON A HILLTOP

It began as a blank canvas onto which I drew hillsides,

Longing for the view as I live in a valley. And of course