(defun my-fast-fib (n)
	   (declare (optimize (safety 0) (debug 0) (speed 3)) ; Give me C-level safety please
		    (type fixnum n)) ; Type declaration
	   (let* ((fib1 1)
		 (fib2 1)
		 (i 2)
		 (fibo fib1))
	     (declare (type fixnum fib1 fib2 i fibo))
	     (loop while (< i n) do
		  (setf
		   fibo (the fixnum (+ fib1 fib2)) ; There are macros that ensure that we use fixnum versions of +, 1+, *, etc. this would let us skip the THE
		   fib1 fib2
		   fib2 fibo
		   i (the fixnum (1+ i))))
	     fibo))