public class Wormhole
{
    public Wormhole (char first, char second, Coordinate location)
    {
        _name = "" + first + second;
        _position = location;
    }

    private String _name;
    private Coordinate _position;
}
@@ -42,20 +42,20 @@
 le (
-char
+Tile
  first, 
 char
@@ -54,12 +54,12 @@
 st, 
-char
+Tile
  sec
@@ -115,22 +115,60 @@
 %22 + 
-first + second
+((Portal) first).getId() + ((Portal) second).getId()
 ;%0A  

Update Wormhole.java