public class Image
{
    /*
     * 144 tiles in the example. Hard wire
     * this for now but could make it dynamic.
     */

    public static final int MAX_X = 12;
    public static final int MAX_Y = 12;

    public Image ()
    {
        _theWorld = new Tile[MAX_Y][MAX_X];

        for (int i = 0; i < MAX_Y; i++)
        {
            for (int j = 0; j < MAX_X; j++)
            {
                _theWorld[i][j] = null;
            }
        }
    }

    private Tile[][] _theWorld;
}
@@ -201,16 +201,77 @@
  = 12;%0A%0A
+    public static final String NO_TILE = %22NO TILE PRESENT%22;%0A%0A
     publ
@@ -512,16 +512,121 @@
 %0A    %7D%0A%0A
+    @Override%0A    public String toString ()%0A    %7B%0A        String str = null;%0A%0A        return str;%0A    %7D%0A%0A
     priv

Update Image.java