diff --git a/03 Animal/python/animal.py b/03 Animal/python/animal.py
index 99e55f45..65263917 100644
--- a/03 Animal/python/animal.py	
+++ b/03 Animal/python/animal.py	
@@ -1,6 +1,51 @@
+########################################################
+#
+# Animal
+#
+# From: Basic computer Games(1978)
+#
+#    Unlike other computer games in which the computer
+#   picks a number or letter and you must guess what it is,
+#   in this game you think of an animal and the computer asks
+#   you questions and tries to guess the name of your animal.
+#   If the computer guesses incorrectly, it will ask you for a
+#   question that differentiates the animal it guessed
+#   from the one you were thinking of. In this way the
+#   computer "learns" new animals. Questions to differentiate
+#   new animals should be input without a question mark.
+#    This version of the game does not have a SAVE feature.
+#   If your sistem allows, you may modify the program to
+#   save array A$, then reload the array  when you want
+#   to play the game again. This way you can save what the
+#   computer learns over a series of games.
+#    At any time if you reply 'LIST' to the question "ARE YOU
+#   THINKING OF AN ANIMAL", the computer will tell you all the
+#   animals it knows so far.
+#    The program starts originally by knowing only FISH and BIRD.
+#   As you build up a file of animals you should use broad,
+#   general questions first and then narrow down to more specific
+#   ones with later animals. For example, If an elephant was to be
+#   your first animal, the computer would ask for a question to distinguish
+#   an elephant from a bird. Naturally there are hundreds of possibilities,
+#   however, if you plan to build a large file of animals a good question
+#   would be "IS IT A MAMAL".
+#    This program can be easily modified to deal with categories of
+#   things other than animals by simply modifying the initial data
+#   in Line 530 and the dialogue references to animal in Lines 10,
+#   40, 50, 130, 230, 240 and 600. In an educational environment, this
+#   would be a valuable program to teach the distinguishing chacteristics
+#   of many classes of objects -- rock formations, geography, marine life,
+#   cell structures, etc.
+#    Originally developed by Arthur Luehrmann at Dartmouth College,
+#   Animal was subsequently shortened and modified by Nathan Teichholtz at
+#   DEC and Steve North at Creative Computing
+#
+########################################################
+
+
 class Node:
     """
-    Nodes of the binary tree of questions.
+    Node of the binary tree of questions.
     """
 
     def __init__(self, text, yes_node, no_node):
@@ -86,7 +131,8 @@ root = Node('Does it swim?', yes_child, no_child)
 
 # Main loop of game
 initial_message()
-keep_playing = parse_input('Are you thinking of an animal? ', True, root) == 'y'
+keep_playing = parse_input(
+    'Are you thinking of an animal? ', True, root) == 'y'
 while keep_playing:
     keep_asking = True
     # Start traversing the tree by the root
@@ -125,3 +171,22 @@ while keep_playing:
 
     keep_playing = parse_input(
         'Are you thinking of an animal? ', True, root) == 'y'
+
+
+########################################################
+# Porting Notes
+#
+#   The data structure used for storing questions and
+#   animals is a binary tree where each non-leaf node
+#   has a question, while the leafs store the animals.
+#
+#   As the original program, this program doesn't store
+#   old questions and animals. A good modification would
+#   be to add a database to store the tree.
+#    Also as the original program, this one can be easily
+#   modified to not only make guesses about animals, by
+#   modyfing the initial data of the tree, the questions
+#   that are asked to the user and the initial message
+#   function  (Lines 120 to 130, 135, 158, 160, 168, 173)
+
+########################################################