> (fac 5)
>(foo 5 1)
>(foo 4 5)
>(foo 3 20)
>(foo 2 60)
>(foo 1 120)
>(foo 0 120)
<120
120
> (and 3 4)
4
> (and #f 4)
#f
> (define a 7)
> (and #f (begin (set! a 42) #t))
#f
> a
7
> 
> (define a 7)
> (my-and #f (begin (set! a 4) #t))
#f
> a
4
> (define a 7) (my-and-lambda (lambda () #f) (lambda () (set! a 42) #t))
#f
> a
7
> (make-vector 3 2)
'#(2 2 2)
> (vector 5 6 7)
'#(5 6 7)
> (list->vector '(a b c))
'#(a b c)
>