task: Закрась все клетки у края поля — получится рамка. Поле каждый раз другого размера.

+---+---+---+---+---+---+---+
|>.   .   .   .   .   .   . |
+   +   +   +   +   +   +   +
| .                       . |
+   +   +   +   +   +   +   +
| .                       . |
+   +   +   +   +   +   +   +
| .                       . |
+   +   +   +   +   +   +   +
| .   .   .   .   .   .   . |
+---+---+---+---+---+---+---+

+---+---+---+---+---+---+---+---+---+---+
| .   .   .   .   .   .   .   .   .   . |
+   +   +   +   +   +   +   +   +   +   +
| .                                   . |
+   +   +   +   +   +   +   +   +   +   +
| .                                   . |
+   +   +   +   +   +   +   +   +   +   +
| .                                   . |
+   +   +   +   +   +   +   +   +   +   +
| .                                   . |
+   +   +   +   +   +   +   +   +   +   +
|^.   .   .   .   .   .   .   .   .   . |
+---+---+---+---+---+---+---+---+---+---+

+---+---+---+---+---+
| .   .   .   .   . |
+   +   +   +   +   +
| .               . |
+   +   +   +   +   +
| .               . |
+   +   +   +   +   +
| .               . |
+   +   +   +   +   +
| .               . |
+   +   +   +   +   +
| .               . |
+   +   +   +   +   +
| .               . |
+   +   +   +   +   +
| .   .   .   .  <. |
+---+---+---+---+---+
