diff --git a/algorithms/a_star.py b/algorithms/a_star.py
new file mode 100644
index 0000000..d3e3077
--- /dev/null
+++ b/algorithms/a_star.py
@@ -0,0 +1,25 @@
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from typing import Tuple, Optional
+
+from common.constants import Direction
+
+
+@dataclass
+class State:
+    position: Tuple[int, int]
+    direction: Direction
+
+
+@dataclass
+class Node:
+    state: State
+    parent: Optional[Node]
+    action: str
+    cost: int = field(init=False)
+    depth: int = field(init=False)
+
+    def __post_init__(self) -> None:
+        self.cost = 0 if not self.parent else self.parent.cost + 1
+        self.depth = self.cost
diff --git a/algorithms/bfs.py b/algorithms/bfs.py
index e900faa..b2ed3d3 100644
--- a/algorithms/bfs.py
+++ b/algorithms/bfs.py
@@ -114,7 +114,7 @@ def go(row, column, direction):
 
 
 def is_valid_move(map, target_row, target_column):
-    if 0 <= target_row < ROWS and 0 <= target_column < COLUMNS and map[target_row][target_column] == ' ':
+    if 0 <= target_row < ROWS and 0 <= target_column < COLUMNS and map[target_row][target_column] in ['g', 's', ' ']:
         return True
 
     return False
diff --git a/common/constants.py b/common/constants.py
index 37dd0ae..692c32d 100644
--- a/common/constants.py
+++ b/common/constants.py
@@ -29,6 +29,7 @@ CASTLE_SPAWN_FIRST_COL = 9
 NBR_OF_WATER = 16
 NBR_OF_TREES = 20
 NBR_OF_MONSTERS = 2
+NBR_OF_SANDS = 15
 
 TILES = [
     'grass1.png',
diff --git a/logic/spawner.py b/logic/spawner.py
index 67431e4..1e91795 100644
--- a/logic/spawner.py
+++ b/logic/spawner.py
@@ -8,7 +8,7 @@ class Spawner:
         self.map = map
 
     def __is_free_field(self, field):
-        return field == ' '
+        return field in ['g', 's', ' ']
 
     def spawn_in_area(self, objects: list, spawn_area_pos_row=0, spawn_area_pos_column=0, spawn_area_width=0,
                       spawn_area_height=0, size=1):
@@ -17,17 +17,17 @@ class Spawner:
         while spawned_objects_count != len(objects):
             x = random.randint(0, spawn_area_height) + spawn_area_pos_row
             y = random.randint(0, spawn_area_width) + spawn_area_pos_column
-            if x < ROWS-1 and y < COLUMNS-1 and self.__is_free_field(self.map[x][y]):
+            if x < ROWS - 1 and y < COLUMNS - 1 and self.__is_free_field(self.map[x][y]):
                 for i in range(size):
                     for j in range(size):
-                        self.map[x-i][y-j] = objects[spawned_objects_count]
+                        self.map[x - i][y - j] = objects[spawned_objects_count]
                 spawned_objects_count += 1
 
     def spawn_where_possible(self, objects: list):
         spawned_objects_count = 0
         while spawned_objects_count != len(objects):
-            x = random.randint(0, ROWS-1)
-            y = random.randint(0, COLUMNS-1)
+            x = random.randint(0, ROWS - 1)
+            y = random.randint(0, COLUMNS - 1)
             if self.__is_free_field(self.map[x][y]):
                 self.map[x][y] = objects[spawned_objects_count]
                 spawned_objects_count += 1