diff --git a/examples/board_extreme_1.txt b/examples/board_extreme_1.txt
new file mode 100644
index 0000000..6e52f3a
--- /dev/null
+++ b/examples/board_extreme_1.txt
@@ -0,0 +1,9 @@
+ 5   4   
+     3  8
+7     9  
+ 3  91   
+   7   36
+  2   8  
+6 8   4 3
+    2  6 
+    67   
diff --git a/examples/board_hard_5.txt b/examples/board_hard_5.txt
new file mode 100644
index 0000000..2df045a
--- /dev/null
+++ b/examples/board_hard_5.txt
@@ -0,0 +1,9 @@
+     579 
+   8    6
+  56 94 3
+4    39  
+ 9    21 
+ 8  943  
+ 5   1 7 
+3 8  214 
+ 2 9  6 5