hit-wall?

  ;; [Listof Posn] -> Boolean
  ;; is any of the drops touching the wall? 
  (define (hit-wall?.v0 lop)
    (cond
      [(empty? lop) false]
      [else (or (hit-wall-1? (first lop)) 
                (hit-wall? (rest lop)))]))

  ;; hit-wall-1? : Posn -> Boolean 
  ;; is a single drop touching the wall? 
  (define (hit-wall-1? p)
    (or (= (posn-x p) 0) (= (posn-x p) 100)
        (= (posn-y p) 0) (= (posn-y p) 100)))

  ;; Tests
  (equal? 
   (hit-wall? (list (make-posn 10 10)
                    (make-posn 100 50)
                    (make-posn 10 10)))
   true)

  (equal? 
   (hit-wall? 
    (list (make-posn 10 10) (make-posn 10 10)))
   false)

Solution:

Grader: Ryan

;; [PTS 1: for ormap and correctness]
(define (hit-wall? lop) (ormap hit-wall-1? lop))