def factorial(x):
    """recursive factorial function"""
    #Base Case
    if x==0:
        ans = 1

    #Recursion x! = x * (x-1)!    
    else:
        print "factorial(" + str(x) + ") calling factorial(" + str(x-1) + ")"
        ans = x * factorial(x-1)

    print "factorial(" + str(x) + ") returning",ans
    return ans



def reverseList(x):
    """reverse a list recursively"""

    #Base Case, a list with a single or no elements
    if len(x) <= 1:
        print "returning ",x
        return x

    #Recursion, reverse the tail of the list and append the head
    else:
        print "calling reverselist(",x[1:], ")"
        ans = reverseList(x[1:])
        
        print "appending " + str(x[0]) + " to ", ans
        ans.append(x[0])
        print "returning ", ans
        return ans