diff --git a/sources/grid.py b/sources/grid.py
index 75e4e46..729dd8d 100644
--- a/sources/grid.py
+++ b/sources/grid.py
@@ -58,38 +58,74 @@ class Grid:
             representation += "\n"
         return representation
 
+    def solve_three(self):
+        for square in self.square_list:
+            if square.is_empty():
+                v_prev = square.prev_vert()
+                v_next = square.next_vert()
+                h_prev = square.prev_horiz()
+                h_next = square.next_horiz()
+
+                if not square.switched and v_prev and v_prev.state != ' ':
+                    v_p_prev = v_prev.prev_vert()
+                    if v_p_prev and v_p_prev.state == v_prev.state:
+                        square.state = v_prev.opposite_state()
+                    elif v_next and v_next.state == v_prev.state:
+                        square.state = v_prev.opposite_state()
+
+                if not square.switched and v_next and v_next.state != ' ':
+                    v_n_next = v_next.next_vert()
+                    if v_n_next and v_n_next.state == v_next.state:
+                        square.state = v_next.opposite_state()
+
+                if not square.switched and h_prev and h_prev.state != ' ':
+                    h_p_prev = h_prev.prev_horiz()
+                    if h_p_prev and h_p_prev.state == h_prev.state:
+                        square.state = h_prev.opposite_state()
+                    elif h_next and h_next.state == h_prev.state:
+                        square.state = h_prev.opposite_state()
+
+                if not square.switched and h_next and h_next.state != ' ':
+                    h_n_next = h_next.next_horiz()
+                    if h_n_next and h_n_next.state == h_next.state:
+                        square.state = h_next.opposite_state()
+
     def solve(self):
-        for k in range(0, 10, 1):
-            for square in self.square_list:
-                if square.is_empty():
-                    v_prev = square.prev_vert()
-                    v_next = square.next_vert()
-                    h_prev = square.prev_horiz()
-                    h_next = square.next_horiz()
+        for i in range(0, 2, 1):
+            self.solve_three()
+            self.solve_same_number()
 
-                    if not square.switched and v_prev and v_prev.state != ' ':
-                        v_p_prev = v_prev.prev_vert()
-                        if v_p_prev and v_p_prev.state == v_prev.state:
-                            square.state = v_prev.opposite_state()
-                        elif v_next and v_next.state == v_prev.state:
-                            square.state = v_prev.opposite_state()
+    def solve_same_number(self):
+        for square in self.square_list:
+            if square.is_empty():
+                same_line = square.same_line()
+                count_red = 0
+                count_blue = 0
+                for line_square in same_line:
+                    if line_square.state == 'B':
+                        count_blue += 1
+                    elif line_square.state == 'R':
+                        count_red += 1
 
-                    if not square.switched and v_next and v_next.state != ' ':
-                        v_n_next = v_next.next_vert()
-                        if v_n_next and v_n_next.state == v_next.state:
-                            square.state = v_next.opposite_state()
+                if count_red == self.size / 2:
+                    square.state = 'B'
+                elif count_blue == self.size / 2:
+                    square.state = 'R'
 
-                    if not square.switched and h_prev and h_prev.state != ' ':
-                        h_p_prev = h_prev.prev_horiz()
-                        if h_p_prev and h_p_prev.state == h_prev.state:
-                            square.state = h_prev.opposite_state()
-                        elif h_next and h_next.state == h_prev.state:
-                            square.state = h_prev.opposite_state()
+                if not square.switched:
+                    same_column = square.same_column()
+                    count_red = 0
+                    count_blue = 0
+                    for line_square in same_column:
+                        if line_square.state == 'B':
+                            count_blue += 1
+                        elif line_square.state == 'R':
+                            count_red += 1
 
-                    if not square.switched and h_next and h_next.state != ' ':
-                        h_n_next = h_next.next_horiz()
-                        if h_n_next and h_n_next.state == h_next.state:
-                            square.state = h_next.opposite_state()
+                    if count_red == self.size / 2:
+                        square.state = 'B'
+                    elif count_blue == self.size / 2:
+                        square.state = 'R'
 
 
 class Square:
@@ -188,39 +224,47 @@ class Square:
         return all_prev_horiz_list
 
     def all_next_horiz(self):
-        h_next = self.prev_horiz()
+        h_next = self.next_horiz()
         all_next_horiz_list = []
         while h_next:
             all_next_horiz_list.append(h_next)
-            h_next = h_next.prev_horiz()
+            h_next = h_next.next_horiz()
         return all_next_horiz_list
 
     def all_prev_vert(self):
-        v_prev = self.prev_horiz()
+        v_prev = self.prev_vert()
         all_prev_vert_list = []
         while v_prev:
             all_prev_vert_list.append(v_prev)
-            v_prev = v_prev.prev_horiz()
+            v_prev = v_prev.prev_vert()
         return all_prev_vert_list
 
     def all_next_vert(self):
-        v_next = self.prev_horiz()
+        v_next = self.next_vert()
         all_next_vert_list = []
         while v_next:
             all_next_vert_list.append(v_next)
-            v_next = v_next.prev_horiz()
+            v_next = v_next.next_vert()
         return all_next_vert_list
 
     def same_line(self):
+        """
+        List of squares in the same line.
+        Does not include the considered square.
+        :return: The list of the squares in the same line.
+        """
         line_list = []
         line_list.extend(self.all_prev_horiz())
-        line_list.append(self)
         line_list.extend(self.all_next_horiz())
         return line_list
 
     def same_column(self):
+        """
+        List of squares in the same column.
+        Does not include the considered square.
+        :return: The list of the squares in the same column.
+        """
         line_list = []
         line_list.extend(self.all_prev_vert())
-        line_list.append(self)
         line_list.extend(self.all_next_vert())
         return line_list