(let ((type a (array int))
      (var howmany int 20)
      (var a a (new-array a howmany 1))
      (var x 2))
  (while
   (< x howmany)
   (begin
     (:= (aref a x) (+ (aref a (- x 1)) (aref a (- x 2))))
     (:= x (+ x 1)))))