diff --git a/strings/camel_case_to_snake_case.py b/strings/camel_case_to_snake_case.py
index 582907be2edb..a01b8e4c06bb 100644
--- a/strings/camel_case_to_snake_case.py
+++ b/strings/camel_case_to_snake_case.py
@@ -5,8 +5,8 @@ def camel_to_snake_case(input_str: str) -> str:
     >>> camel_to_snake_case("someRandomString")
     'some_random_string'
 
-    >>> camel_to_snake_case("SomeRandomStr#ng")
-    'some_random_str_ng'
+    >>> camel_to_snake_case("SomeRandomString")
+    'some_random_string'
 
     >>> camel_to_snake_case("123someRandom123String123")
     '123_some_random_123_string_123'
diff --git a/strings/number_guessing.py b/strings/number_guessing.py
new file mode 100644
index 000000000000..5c727b1cc7a6
--- /dev/null
+++ b/strings/number_guessing.py
@@ -0,0 +1,76 @@
+"""Number Guessing Game.
+
+A simple game where the user guesses a randomly generated number
+within a user-defined range.
+
+Reference: https://en.wikipedia.org/wiki/Guessing_game
+"""
+
+import random
+
+
+def get_top_of_range() -> int:
+    """
+    Get the upper bound of the guessing range from the user.
+
+    >>> isinstance(get_top_of_range(), int)
+    True
+    """
+    top_of_range = input("Enter the upper bound number: ")
+    if top_of_range.isdigit():
+        top_of_range = int(top_of_range)
+        if top_of_range <= 0:
+            print("Please enter a number larger than 0.")
+            quit()
+    else:
+        print("Please enter a valid digit.")
+        quit()
+    return top_of_range
+
+
+def get_guess() -> int:
+    """
+    Get a valid integer guess from the user.
+
+    >>> isinstance(get_guess(), int)
+    True
+    """
+    while True:
+        guess = input("Please make a guess: ")
+        if guess.isdigit():
+            return int(guess)
+        print("Please type a number next time.")
+
+
+def play_game(top_of_range: int) -> int:
+    """
+    Play the number guessing game and return the number of guesses.
+
+    >>> import random
+    >>> random.seed(42)
+    >>> play_game(1)
+    Whoa! You got it.
+    1
+    """
+    random_number = random.randint(0, top_of_range)
+    guesses = 0
+
+    while True:
+        guesses += 1
+        guess = get_guess()
+
+        if guess == random_number:
+            print("Whoa! You got it.")
+            break
+        elif guess < random_number:
+            print("Too low! Try higher.")
+        else:
+            print("Too high! Try lower.")
+
+    return guesses
+
+
+if __name__ == "__main__":
+    top = get_top_of_range()
+    total_guesses = play_game(top)
+    print(f"You got it in {total_guesses} guesses!")
diff --git a/strings/secret_language.py b/strings/secret_language.py
new file mode 100644
index 000000000000..98d5f098e062
--- /dev/null
+++ b/strings/secret_language.py
@@ -0,0 +1,93 @@
+# Encoding & Decoding
+
+import random
+import string
+
+
+def random_chars() -> str:
+    """
+    Generate a random string of 3 ASCII letters.
+
+    >>> import random
+    >>> len(random_chars()) == 3
+    True
+
+
+    >>> all(c in string.ascii_letters for c in random_chars())
+    True
+
+
+
+    """
+    return "".join(random.choices(string.ascii_letters, k=3))
+
+
+def random_digits() -> str:
+    """
+    create a random string of 3 digits.
+
+     >>> len(random_digits()) == 3
+     True
+
+
+
+     >>> all(c in string.digits for c in random_digits())
+     True
+    """
+    return "".join(random.choices(string.digits, k=3))
+
+
+def encode(code: str) -> str:
+    """
+    Encode a string by shifting the first character to the end and
+    wrapping it with random padding of 3 letters and 3 digits on each side.
+
+    Reference: https://en.wikipedia.org/wiki/Caesar_cipher
+
+    >>> len(encode('hello')) == len('hello') + 12
+    True
+    >>> len(encode('hi')) == len('hi') + 12
+    True
+
+
+    """
+    if len(code) >= 3:
+        code = code[1:] + code[0]
+        code = (
+            random_chars() + random_digits() + code + random_digits() + random_chars()
+        )
+    else:
+        code = code[::-1]
+        code = (
+            random_chars() + random_digits() + code + random_digits() + random_chars()
+        )
+    return code
+
+
+def decode(code: str) -> str:
+    """
+    Decode an encoded string by stripping the random padding and
+    reversing the character shift.
+
+    >>> decode(encode('hello'))
+    'hello'
+    >>> decode(encode('hi'))
+    'hi'
+    >>> decode(encode('python'))
+    'python'
+
+
+
+    """
+    code = code[6:-6]
+    code = code[-1] + code[:-1] if len(code) >= 3 else code[::-1]
+    return code
+
+
+if __name__ == "__main__":
+    code = input("Enter the code: ")
+    encoded = encode(code)
+    decoded = decode(encoded)
+    print(f"Original → {code}")
+    print(f"Encoded  → {encoded}")
+    print(f"Decoded  → {decoded}")