Wall

public class Wall extends Location {
  int r, c;

    public Wall (int r, int c) {
    super (r, c);
    }

    public boolean isValid () {
        return false;
    }

    public boolean hasDot() {
      return false;
    }

    public boolean isOccupied() {
      return false;
    }

    public void setDot (Dot d) {}



}