diff --git a/wfgy_sdk/bbpf.py b/wfgy_sdk/bbpf.py
new file mode 100644
index 00000000..f2ef45b0
--- /dev/null
+++ b/wfgy_sdk/bbpf.py
@@ -0,0 +1,11 @@
+import numpy as np
+
+def perturb_state(x, epsilon=0.1, num_paths=3):
+    """Return list of perturbed states"""
+    return [x + np.random.normal(0, epsilon, size=x.shape) for _ in range(num_paths)]
+
+def run_demo():
+    x = np.array([1.0, 2.0, 3.0])
+    paths = perturb_state(x)
+    for i, p in enumerate(paths):
+        print(f"Path {i+1}: {p}")