I'm wondering whether you meant "recursive". Here is a simple example of a recursive function to compute the factorial function:

def factorial(n):
if n == 0:
return 1
else:
return n * factorial(n - 1)

The two key elements of a recursive algorithm are:

- The termination condition: n == 0
- The reduction step where the function calls itself with a smaller number each time: factorial(n - 1)