(let ((a 10) (b 11) (c 12) (d 13))
  (letrec ((g (lambda (a b c d)
                (+ a b c d)))
           (f (lambda (a b c d)
                (g a b c d))))
    (f 1 2 3 4)))

; With static binding: 10. 
; With dynamic binding: 10.