THE QUALITY OF ORIGINALITY is often strained in our judgments of artists, be they painters, sculptors or illustrators of children’s books. In a recent profile of Louise Nevelson in the Sunday Times Magazine, the sculptor speaks of her earliest encouragement by an art teacher in grade school: “. . . She held this up [Louise’s drawing of a flower] and said it was the best because it was original. That word was very big to a child. I clocked it; I knew that to be original was what it was all about.”Perhaps the most refreshing impression one took from the recent exhibition of “The Art of Maurice