diff --git a/main.py b/main.py
index 8d730a7..e386129 100644
--- a/main.py
+++ b/main.py
@@ -22,8 +22,7 @@ def main():
 
     while '.' in string:
         new_string = iterate_board(string)
-        if new_string == string:
-            break
+        assert new_string != string
         string = new_string