diff --git a/command.py b/command.py
index a2ccac57..972c0209 100644
--- a/command.py
+++ b/command.py
@@ -4,43 +4,164 @@
 import os
 
 
-class MoveFileCommand(object):
-    def __init__(self, src, dest):
-        self.src = src
-        self.dest = dest
+# class MoveFileCommand(object):
+#     def __init__(self, src, dest):
+#         self.src = src
+#         self.dest = dest
+
+#     def execute(self):
+#         self()
+
+#     def __call__(self):
+#         print('renaming {} to {}'.format(self.src, self.dest))
+#         os.rename(self.src, self.dest)
+
+#     def undo(self):
+#         print('renaming {} to {}'.format(self.dest, self.src))
+#         os.rename(self.dest, self.src)
+
+
+# def main():
+#     command_stack = []
+
+#     # commands are just pushed into the command stack
+#     command_stack.append(MoveFileCommand('foo.txt', 'bar.txt'))
+#     command_stack.append(MoveFileCommand('bar.txt', 'baz.txt'))
+
+#     # they can be executed later on
+#     for cmd in command_stack:
+#         cmd.execute()
+
+#     # and can also be undone at will
+#     for cmd in reversed(command_stack):
+#         cmd.undo()
+
+# if __name__ == "__main__":
+#     main()
+
+### OUTPUT ###
+# renaming foo.txt to bar.txt
+# renaming bar.txt to baz.txt
+# renaming baz.txt to bar.txt
+# renaming bar.txt to foo.txt
+
+#---------------------------------------------#
+
+#---------------------------------------#
+# my command pattern
+#---------------------------------------#
+
+class Vehicle(object):
+    """docstring for ClassName"""
+    def __init__(self):
+        self.name = 'vehicle'
+        
+    def __call__(self):
+        print "travelling by a Vehicle"
 
     def execute(self):
         self()
 
+
+class Bus(Vehicle):
+    """docstring for Bus"""
+    def __init__(self):
+        super(Vehicle, self).__init__()
+        self.name = 'bus'
+
     def __call__(self):
-        print('renaming {} to {}'.format(self.src, self.dest))
-        os.rename(self.src, self.dest)
+        print 'travelling by bus'
 
-    def undo(self):
-        print('renaming {} to {}'.format(self.dest, self.src))
-        os.rename(self.dest, self.src)
+    def execute(self):
+        self()
+        
+class Bike(Vehicle):
+    """docstring for Bike"""
+    def __init__(self):
+        super(Vehicle, self).__init__()
+        self.name = 'bike'
+
+    def __call__(self):
+        print 'travelling by bike'
+
+    def execute(self):
+        self()
+
+class Car(Vehicle):
+    """docstring for Car"""
+    def __init__(self):
+        super(Vehicle, self).__init__()
+        self.name = 'car'
+
+    def __call__(self):
+        print 'travelling by car'
+
+    def execute(self):
+        self()
+
+class Rocket(Vehicle):
+    """docstring for Rocket"""
+    def __init__(self):
+        super(Vehicle, self).__init__()
+        self.name = 'rocket'
+
+    def __call__(self):
+        print 'travelling by rocket'
+
+    def execute(self):
+        self()
+
+
+class Traveller(object):
+    """docstring for Traveller"""
+    def __init__(self, name):
+        self.name = name
+
+    def set_vehicle(self, vehicle):
+        self.vehicle = vehicle
+        
+    def travel(self):
+        self.vehicle.execute()
 
 
 def main():
-    command_stack = []
+    # create a traveller
+    tom = Traveller('tom')
 
-    # commands are just pushed into the command stack
-    command_stack.append(MoveFileCommand('foo.txt', 'bar.txt'))
-    command_stack.append(MoveFileCommand('bar.txt', 'baz.txt'))
+    print 'stop 1:'
+    # traveller's first vehicle
+    vehicle = Bus()
+    tom.set_vehicle(vehicle)
+    tom.travel()
 
-    # they can be executed later on
-    for cmd in command_stack:
-        cmd.execute()
+    print 'stop 2:'
+    # traveller's second vehicle
+    vehicle = Bike()
+    tom.set_vehicle(vehicle)
+    tom.travel()
 
-    # and can also be undone at will
-    for cmd in reversed(command_stack):
-        cmd.undo()
+    print 'stop 3:'
+    # traveller's third vehicle
+    vehicle = Car()
+    tom.set_vehicle(vehicle)
+    tom.travel()
 
-if __name__ == "__main__":
+    print 'stop 4:'
+    # traveller's fourth vehicle
+    vehicle = Rocket()
+    tom.set_vehicle(vehicle)
+    tom.travel()
+
+if __name__ == '__main__':
     main()
 
+
 ### OUTPUT ###
-# renaming foo.txt to bar.txt
-# renaming bar.txt to baz.txt
-# renaming baz.txt to bar.txt
-# renaming bar.txt to foo.txt
+# stop 1:
+# travelling by bus
+# stop 2:
+# travelling by bike
+# stop 3:
+# travelling by car
+# stop 4:
+# travelling by rocket
\ No newline at end of file