Playing around with mazes, generate and solve.
+----+----+----+----+----+
| 0 1 2 3 4 |
+----+ + +----+ |
| 3 2 | 3 4 | 5 |
+ +----+----+ + |
| 4 | 7 6 5 | 6 |
+----+ +----+----+----|
| 9 8 9 10 11 |
+----+ +----+ + |
| 10 9 | 12 11 | 12 |
+----+----+----+----+----+
