0 xE** -> N 0
0 *x** -> E 2
0 NEx* -> W 3
0 NEWx -> S 1

1 **Wx -> S 1
1 **x* -> W 3
1 *xWS -> E 2
1 xEWS -> N 0

2 *x*S -> E 2
2 ***x -> S 1
2 xE*S -> N 0
2 NExS -> W 3

3 N*x* -> W 3
3 x*** -> N 0
3 N*Wx -> S 1
3 NxWS -> E 2