Read the excerpt from "Choice: A Tribute to Dr. Martin Luther King, Jr.” by Alice Walker. But add to all of these things the one thing that seems to me second to none in importance: He gave us back our heritage. He gave us back our homeland; the bones and dust of our ancestors, who may now sleep within our caring and our hearing. He gave us the blueness of the Georgia sky in autumn as in summer; the colors of the Southern winter as well as glimpses of the green of vacation-time spring. Those of our relatives we used to invite for a visit we now can ask to stay. . . . He gave us full-time use of our own woods, and restored our memories to those of us who were forced to run away, as realities we might each day enjoy and leave for our children. What does Walker emphasize with the metaphor in this excerpt?