Sculpture should always at first sight have some obscurities, and further meanings. People should want to go on looking and thinking; it should never tell all about itself immediately. Initially both sculpture and painting must need effort to be fully appreciated, or else it is just an empty immediacy like a poster, which is designed to be read by the people on top of a bus in half a second. In fact all art should have some more mystery and meaning to it than is apparent to a quick observer.

Henry Moore