+-----+-----+-----+-----+-----+-----+-----+-----+-----+
|                                                     |
|  1  X  3  X  5  X     X     X     X     X     X     |
|                                                     |
+  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +
|                                                     |
|     X     X     X  5  X  8  X  4  X     X     X     |
|                                                     |
+  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +
|                                                     |
|  8  X     X  7  X     X     X     X  2  X  5  X  9  |
|                                                     |
+  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +
|                                                     |
|     X  6  X     X     X     X     X     X     X     |
|                                                     |
+  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +
|                                                     |
|  9  X     X  8  X     X     X     X  5  X     X  6  |
|                                                     |
+  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +
|                                                     |
|     X     X     X     X     X     X     X  8  X     |
|                                                     |
+  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +
|                                                     |
|  2  X  5  X  9  X     X     X     X  8  X     X  7  |
|                                                     |
+  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +
|                                                     |
|     X     X     X  9  X  4  X  8  X     X     X     |
|                                                     |
+  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +  X  +
|                                                     |
|     X     X     X     X     X     X  3  X  9  X  1  |
|                                                     |
+-----+-----+-----+-----+-----+-----+-----+-----+-----+