diff --git a/Tetris.py b/Tetris.py
index 9956eef..dc55366 100644
--- a/Tetris.py
+++ b/Tetris.py
@@ -1,5 +1,6 @@
 import sys
 import pygame
+
 from util.ConfigurationManager import ConfigurationManager
 from util.PieceGenerator import PieceGenerator 
 from entity.Well import Well
@@ -15,7 +16,7 @@ class Tetris:
         self.well = None
         self.current_piece = None
 
-    def initialize(self):
+    def initialize(self) -> None:
         pygame.init()
 
         win_width = ConfigurationManager.configuration["window"]["width"]
@@ -34,7 +35,7 @@ class Tetris:
         pygame.display.set_icon(loaded_icon)
 
     # gets called from the games main loop
-    def update(self):
+    def update(self) -> None:
         # TODO write not initialized exception
 
         self.clock.tick(self.fps)
@@ -58,8 +59,10 @@ class Tetris:
                         self.current_piece.move((0, self.tile_size))
                 if event.key == pygame.K_z:
                     self.__generate_piece((300, 100))
+                if event.key == pygame.K_x:
+                    self.current_piece.revert()
 
-    def draw(self):
+    def draw(self) -> None:
         # TODO write not initialized exception
 
         # draw window bg
diff --git a/entity/Entity.py b/entity/Entity.py
new file mode 100644
index 0000000..e1ec1af
--- /dev/null
+++ b/entity/Entity.py
@@ -0,0 +1,14 @@
+import pygame
+
+class Entity:
+    def __init__(self):
+        pass
+
+    def update(self) -> None:
+        pass
+
+    def draw(self, surface: pygame.Surface) -> None:
+        pass
+
+    def collide(self, entity) -> bool:
+        pass
diff --git a/entity/Piece.py b/entity/Piece.py
index a6217c3..7cf5b82 100644
--- a/entity/Piece.py
+++ b/entity/Piece.py
@@ -1,19 +1,27 @@
+from typing import List, Tuple
 import pygame
+import copy
 
+from entity.Entity import Entity
 from util.ConfigurationManager import ConfigurationManager
 
 ''' 
     For information on the Tetris piece Tetromino go here:
     https://tetris.fandom.com/wiki/Tetromino
 '''
-class Piece: # TODO game objects base class / interface? 
+class Piece(Entity):
         
-    def __init__(self, shape, position, color):
+    def __init__(self, shape: Tuple, position: Tuple, color: str):
+        super().__init__()
+
         self.color = color
         self.points = self.__get_points(shape, position)
         self.center = self.__get_center(shape, position)
 
-    def draw(self, surface):
+        self.previous_points = None
+        self.previous_center = None
+
+    def draw(self, surface: pygame.Surface) -> None:
         tile_size = ConfigurationManager.configuration["engine"]["tile-size"]
         hex_color = ConfigurationManager.configuration["color"]["border"] # TODO should abstract out color call?
 
@@ -24,7 +32,10 @@ class Piece: # TODO game objects base class / interface?
             pygame.draw.polygon(surface, base_color, sub_points, 0)
             pygame.draw.polygon(surface, border_color, sub_points, max(tile_size // 6, 1))
 
-    def move(self, vector):
+    def move(self, vector: Tuple) -> None:
+        self.previous_points = copy.deepcopy(self.points)
+        self.previous_center = copy.deepcopy(self.center)
+
         self.center[0] += vector[0]
         self.center[1] += vector[1]
 
@@ -37,7 +48,10 @@ class Piece: # TODO game objects base class / interface?
         For more information on a rotation of a piece go here:
         https://gamedev.stackexchange.com/questions/17974/how-to-rotate-blocks-in-tetris
     '''
-    def rotate(self):
+    def rotate(self) -> None:
+        self.previous_points = copy.deepcopy(self.points)
+        self.previous_center = copy.deepcopy(self.center)
+
         for sub_points in self.points:
             for point in sub_points:
                 h = point[0] - self.center[0]
@@ -46,11 +60,13 @@ class Piece: # TODO game objects base class / interface?
                 point[0] = (k * -1) + self.center[0]
                 point[1] = h + self.center[1]
 
-    def colliding(object):
-        pass
+    def revert(self) -> None:
+        if self.previous_points and self.previous_center:
+            self.points = self.previous_points
+            self.center = self.previous_center
 
-    def __get_points(self, shape, position):
-        tile_size = ConfigurationManager.configuration["engine"]["tile-size"]
+    def __get_points(self, shape: Tuple, position: Tuple) -> List:
+        tile_size =  ConfigurationManager.configuration["engine"]["tile-size"]
 
         points = []
         for square in shape[:-1]:
@@ -62,7 +78,7 @@ class Piece: # TODO game objects base class / interface?
 
         return points
 
-    def __get_center(self, shape, position):
+    def __get_center(self, shape: Tuple, position: Tuple) -> List:
         tile_size = ConfigurationManager.configuration["engine"]["tile-size"]
         center = shape[-1]
 
diff --git a/entity/Well.py b/entity/Well.py
index 7bb44f9..f27798c 100644
--- a/entity/Well.py
+++ b/entity/Well.py
@@ -1,23 +1,25 @@
+from typing import List, Tuple
 import pygame
 
+from entity.Entity import Entity
 from util.ConfigurationManager import ConfigurationManager
  
-class Well: # TODO game objects base class / interface? 
+class Well(Entity):
     
     WIDTH = 10 # standard tetris well width, should not be changed
     HEIGHT = 20 # standard tetris well height, should not be changed
 
-    def __init__(self, position):
+    def __init__(self, position: Tuple):
         self.points = self.__get_points(position)
 
-    def draw(self, surface):
+    def draw(self, surface: pygame.Surface) -> None:
         well_color_hex = ConfigurationManager.configuration["color"]["border"] # TODO Should abstract out color call?
         well_color = pygame.Color(well_color_hex)
 
         for sub_points in self.points:
             pygame.draw.polygon(surface, well_color, sub_points, 0)
 
-    def __get_points(self, position):
+    def __get_points(self, position: Tuple) -> List:
         tile_size = ConfigurationManager.configuration["engine"]["tile-size"]
 
         shape = []
diff --git a/main.py b/main.py
index e1c78c9..421e3e2 100644
--- a/main.py
+++ b/main.py
@@ -4,10 +4,12 @@
     https://tetris.com/play-tetris
 '''
 
+# TODO review imports to make sure it is being done correctly
+
 from Tetris import Tetris
 from util.ConfigurationManager import ConfigurationManager
 
-def main():
+def main() -> None:
     ConfigurationManager.load()
 
     tetris = Tetris()
diff --git a/util/ConfigurationManager.py b/util/ConfigurationManager.py
index a0f6105..83b143d 100644
--- a/util/ConfigurationManager.py
+++ b/util/ConfigurationManager.py
@@ -8,6 +8,6 @@ class ConfigurationManager:
     configuration = []
 
     @classmethod
-    def load(cls):
+    def load(cls) -> None:
         with open(CONFIG_FILE_LOCATION, "r") as yaml_file:
             cls.configuration = yaml.safe_load(yaml_file)
\ No newline at end of file
diff --git a/util/PieceGenerator.py b/util/PieceGenerator.py
index c347e00..d6d0ace 100644
--- a/util/PieceGenerator.py
+++ b/util/PieceGenerator.py
@@ -1,3 +1,4 @@
+from typing import Tuple
 import random
 
 from entity.Piece import Piece
@@ -11,20 +12,20 @@ class PieceGenerator:
     __bucket = []
 
     @classmethod
-    def get_piece(cls, position):
+    def get_piece(cls, position: Tuple) -> Piece:
         if len(cls.__bucket) == 0:
             cls.__generate_bucket()
 
         return Piece(cls.__get_piece_shape(cls.__bucket.pop()), position, cls.__get_piece_color())
 
     @classmethod
-    def __generate_bucket(cls):
+    def __generate_bucket(cls) -> None:
         piece_types = list(range(7))
         while len(cls.__bucket) != 7:
             random_number = random.randint(0, 6 - len(cls.__bucket))
             cls.__bucket.append(piece_types.pop(random_number))
 
-    def __get_piece_shape(piece_number):
+    def __get_piece_shape(piece_number: int) -> Tuple:
         if piece_number == 0:
             return Piece.I_SHAPE
         if piece_number == 1:
@@ -42,6 +43,6 @@ class PieceGenerator:
 
         return None
 
-    def __get_piece_color():
+    def __get_piece_color() -> str:
         random_number = random.randint(1, 3)
         return ConfigurationManager.configuration["color"]["base-" + str(random_number)]