Suppose we define the procedure

(define (f g)
  (g 2))

Then we have

(f square)
4

(f (lambda (z) (* z (+ z 1))))
6

What happens if we (perversely) ask the interpreter to evaluate the combination (f f)? Explain.

Answer: Failure, because (f f) evaluates to (f 2), but then we get (2 2); the first 2 is not a function so the interpreter fails.