diff --git a/buggy.py b/buggy.py
--- a/buggy.py
+++ b/buggy.py
@@ -17,7 +17,7 @@
                 for shift_c in range(w1):
                     if bit_c >> shift_c & 1 == 0:
                         after_row.append(a[shift_r][shift_c])
-                    after.append(after_row)
+                after.append(after_row)
         if after == b:
             print("Yes")
             exit()
