diff --git a/GameLogic.py b/GameLogic.py
index 7fe3438..8c9fcf0 100644
--- a/GameLogic.py
+++ b/GameLogic.py
@@ -19,10 +19,31 @@ class GameLogic():
         pass
     
     
-    def check_for_win(self, playerList):
-        for player in playerList:
-            pass
+    def check_who_win(self):
+        # Should have used vectors instead of committing tuples mithosis,
+        # but whatever, it works anyway, and if it works, why code more
+        # for nothing?
+        for player in self.playerList:
+            markList = player.get_markList()
+            # since every mark is checked, there's no need to go into
+            # opposite directions, so, there is (0,1) but no (0, -1).
+            # This twice decreases the amount of computation needed.
+            directions = ((0, 1), (1, 0), (1,1), (-1, 1))
+            for mark in markList:
+                for direction in directions:
+                    if self.is_line(markList, mark, direction):
+                        return player
+            return False
     
+    def is_line(self, markList, mark, direction): # INTERNAL, I guess.
+        for i in range(1, self.winRowLength):
+            seeked = (mark[0] + direction[0] * i, mark[1] + direction[1] * i)
+            if seeked in markList:
+                continue
+            else:
+                return False
+        return True
+                   
     def get_time(self):
         return str(datetime.now() - self.startTime)