+----+---------+----+---------+        
| 1  |         |    |    5    |  
+----+         | 4  +---------+
| 2  |    3    |    |    6    |    
+----+         +----+---------+       
|    |         |   east       |
|    +---------+    +---------+
|  west        |    |         |
+----+----+----+----|   10    |
|    |    |  south  |         |   
|    |    +----+    +----+----+      
| 7  |  8 |    |    |    |    |    
|    |    | 9  |    | 11 | 12 |
|    |    |    |    |    |    |   
+----+----+----+----+----+----+

The plan above shows an arrangement of corn, wheat and rye fields. Jack is in the middle of one of the fields and has to meet his father in the middle of another field.

On his journey from the field he is in to the field his father is in.

1. His route takes him continuously through each of five other fields exactly once.
2. He (being allergic to rye) avoids going through any part of a rye field.
3. He notices no two fields of the same kind border on each other.

Which L-shaped field - east, west, or south- is a rye field?