You're right about Fibonacci - a naive fib(1000) takes a long time to eventually overflow the stack in python. But fact(1000) quickly crashes. Which is a shame

You're right about Fibonacci - a naive fib(1000) takes a long time to eventually overflow the stack in python. But fact(1000) quickly crashes. Which is a shame as python has a full(?) number tower and has no problem calculating 1000!