diff --git a/litris.py b/litris.py
index 9b2b224..8dbde94 100644
--- a/litris.py
+++ b/litris.py
@@ -277,16 +277,16 @@ class Litris(GameBase):
             # Z1
             for e in range(19, 17, - 1):
                 for i in range(0, 18, 1):
-                    if current_board[e][i] == 1 and current_board[e][i + 1] == 0 and current_board[e][i + 2] == 0 and current_board[e - 1][i] == 0 and current_board[e - 1][i + 1] == 0:
+                    if current_board[e][i] == 0 and current_board[e][i + 1] == 0 and current_board[e][i + 2] == 1 and current_board[e - 1][i + 1] == 0 and current_board[e - 1][i + 2] == 0:
                         return i - Z1_COL
         elif np.array_equal(stone, Z2_FULL):
             # Z2
             for e in range(19, 17, - 1):
                 for i in range(0, 18, 1):
-                    if current_board[e][i] == 0 and current_board[e][i + 1] == 0 and current_board[e][i + 2] == 1 and current_board[e - 1][i + 1] == 0 and current_board[e - 1][i + 2] == 0:
+                    if current_board[e][i] == 1 and current_board[e][i + 1] == 0 and current_board[e][i + 2] == 0 and current_board[e - 1][i] == 0 and current_board[e - 1][i + 1] == 0:
                         return i - Z2_COL
         elif np.array_equal(stone, T1_FULL):
-            # L1
+            # T1
             for e in range(19, 17, - 1):
                 for i in range(0, 18, 1):
                     if current_board[e][i] == 1 and current_board[e][i + 1] == 0 and current_board[e][i + 2] == 1 and current_board[e - 1][i] == 0 and current_board[e - 1][i + 1] == 0 and current_board[e - 1][i + 2] == 0: