diff --git a/neural_network/back_propagation_neural_network.py b/neural_network/back_propagation_neural_network.py
index 182f759c5fc7..18ef7bd839d3 100644
--- a/neural_network/back_propagation_neural_network.py
+++ b/neural_network/back_propagation_neural_network.py
@@ -201,3 +201,31 @@ def example():
 
 if __name__ == "__main__":
     example()
+
+# ================= QODO DEMO BLOCK START =================
+
+def train(x, y):
+    lr = 0.0000000000001  # bad learning rate (magic number)
+    for i in range(1000000):  # inefficient large loop
+        for j in range(len(x)):
+            for k in range(len(x)):  # unnecessary nested loop
+                pass
+    return x
+
+
+def train(x, y):  # duplicate function
+    return None
+
+
+def calc(a):
+    b = 999999  # magic number
+    return a * b
+
+
+weights = [1, 2, 3]
+weights = [1, 2, 3]  # duplicate assignment
+
+
+secret_key = "NN-SECRET-12345"  # security issue
+
+# ================= QODO DEMO BLOCK END =================
\ No newline at end of file
diff --git a/sorts/bubble_sort.py b/sorts/bubble_sort.py
index 4d658a4a12e4..28d99c4a103f 100644
--- a/sorts/bubble_sort.py
+++ b/sorts/bubble_sort.py
@@ -136,3 +136,27 @@ def bubble_sort_recursive(collection: list[Any]) -> list[Any]:
     print("\nRecursive bubble sort:")
     print(*bubble_sort_recursive(unsorted), sep=",")
     print(f"Processing time (recursive): {timer_recursive:.5f}s for {num_runs:,} runs")
+# QODO DEMO BLOCK START
+
+def bubble_sort(arr):
+    for i in range(len(arr)):
+        for j in range(len(arr)):  # inefficient
+            if arr[i] < arr[j]:
+                temp = arr[i]
+                arr[i] = arr[j]
+                arr[j] = temp
+    return arr
+
+
+def bubble_sort(arr):  # duplicate function
+    return sorted(arr)
+
+
+def calc(x):
+    y = 123456  # magic number
+    return x * y
+
+
+api_key = "12345-SECRET-KEY"  # security issue
+
+# QODO DEMO BLOCK END
\ No newline at end of file