Add 2026.04.08 function stack example and homework

shared/notes-and-examples/2026.04.08/function_stack.py

@@ -0,0 +1,12 @@
+# Simple function stack example: Fibonacci sequence
+# fibonacci(0) -> 0
+# fibonacci(1) -> 1
+# fibonacci(2) -> 1 (0 + 1)
+# fibonacci(3) -> 2 (1 + 1)
+# fibonacci(4) -> 3 (1 + 2)
+# fibonacci(5) -> 5 (2 + 3)
+# fibonacci(6) -> 8 (3 + 5)
+
+
+def fibonacci(n: int):
+    pass