diff --git a/8.rkt b/8.rkt
index e031f9c..4223810 100644
--- a/8.rkt
+++ b/8.rkt
@@ -4,50 +4,49 @@
 
 ;; solution for day 8
 
-(define (visible? grid y x)
-  (define h (vector-length grid))
-  (define w (vector-length (vector-ref grid 0)))
-  (define v (vector-ref (vector-ref grid y) x))
-  (cond
-    [(= 0 y) #t]
-    [(= 0 x) #t]
-    [(= (sub1 h) y) #t]
-    [(= (sub1 w) x) #t]
-    [else
-      (or
-        (for/and ([x* (in-range 0 x)])
-          (< (vector-ref (vector-ref grid y) x*) v))
-        (for/and ([x* (in-range (add1 x) w)])
-          (< (vector-ref (vector-ref grid y) x*) v))
-        (for/and ([y* (in-range 0 y)])
-          (< (vector-ref (vector-ref grid y*) x) v))
-        (for/and ([y* (in-range (add1 y) h)])
-          (< (vector-ref (vector-ref grid y*) x) v)))]))
+(define (g-ref grid y x)
+  (vector-ref (vector-ref grid y) x))
 
+(define (g-size grid)
+  (values (vector-length grid) (vector-length (vector-ref grid 0))))
 
-(define (part1 input)
-  (define h (vector-length input))
-  (define w (vector-length (vector-ref input 0)))
+(define (part1 grid)
+  (define-values [h w] (g-size grid))
 
-  (for*/sum ([x (in-range w)] [y (in-range h)]
-             #:when (visible? input y x))
+  (define (visible? y x)
+    (define v (g-ref grid y x))
+    (cond
+      [(= 0 y) #t]
+      [(= 0 x) #t]
+      [(= (sub1 h) y) #t]
+      [(= (sub1 w) x) #t]
+      [else
+        (or
+          (for/and ([x* (in-range 0 x)])
+            (< (g-ref grid y x*) v))
+          (for/and ([x* (in-range (add1 x) w)])
+            (< (g-ref grid y x*) v))
+          (for/and ([y* (in-range 0 y)])
+            (< (g-ref grid y* x) v))
+          (for/and ([y* (in-range (add1 y) h)])
+            (< (g-ref grid y* x) v)))]))
+
+  (for*/sum ([x (in-range w)] [y (in-range h)] #:when (visible? y x))
     1))
 
-
-(define (part2 input)
-  (define h (vector-length input))
-  (define w (vector-length (vector-ref input 0)))
+(define (part2 grid)
+  (define-values [h w] (g-size grid))
 
   (define (scenic-score y x)
-    (define v (vector-ref (vector-ref input y) x))
+    (define v (g-ref grid y x))
     (*
-      (for/sum ([x* (in-range (sub1 x) -1 -1)] #:final (>= (vector-ref (vector-ref input y) x*) v))
+      (for/sum ([x* (in-range (sub1 x) -1 -1)] #:final (>= (g-ref grid y x*) v))
         1)
-      (for/sum ([x* (in-range (add1 x) w)] #:final (>= (vector-ref (vector-ref input y) x*) v))
+      (for/sum ([x* (in-range (add1 x) w)] #:final (>= (g-ref grid y x*) v))
         1)
-      (for/sum ([y* (in-range (sub1 y) -1 -1)] #:final (>= (vector-ref (vector-ref input y*) x) v))
+      (for/sum ([y* (in-range (sub1 y) -1 -1)] #:final (>= (g-ref grid y* x) v))
         1)
-      (for/sum ([y* (in-range (add1 y) h)] #:final (>= (vector-ref (vector-ref input y*) x) v))
+      (for/sum ([y* (in-range (add1 y) h)] #:final (>= (g-ref grid y* x) v))
         1)))
 
   (apply max