The Universal Flow Chart.
The Universal Flow Chart deals with the usual case where the problem splits into pieces which can be handled one-by-one in sequence. But if there are special cases where the problem can be solved immediately, handle them first. This sounds an awful lot like recursion.
You have likely seen the Fibonacci Series before. This is a series of integers, where the n'th integer is the series is given by
Fib( 1 ) == 1 Fib( 2 ) == 1 Fib( n ) == Fib(n-1) + Fib(n-2)
The first few terms of the series are
1, 1, 2, 3, 5, 8, 13, 21, 34, 55, ...
What are the special cases that might be handled with early returns?