public class Tile
{
    public Tile (char type)
    {
        _type = type;
    }

    public char type ()
    {
        return _type;
    }
    
    public boolean isBug ()
    {
        return TileId.BUG == _type;
    }

    @Override
    public String toString ()
    {
        return Character.toString(_type);
    }

    private char _type;
}
@@ -6,20 +6,20 @@
 c class 
-Tile
+Cell
 %0A%7B%0A    p
@@ -24,20 +24,20 @@
  public 
-Tile
+Cell
  (char t
@@ -164,11 +164,17 @@
 n is
-Bug
+EmptySeat
  ()%0A
@@ -198,18 +198,25 @@
 urn 
-TileId.BUG
+CellId.EMPTY_SEAT
  == 

Update Cell.java