diff --git a/menelaus.scm b/menelaus.scm
index 6fcabf8..8415eab 100644
--- a/menelaus.scm
+++ b/menelaus.scm
@@ -2,18 +2,21 @@
 
 (include "keycodes.scm")
 
-(define columns (list 0 1 2 3 4 5 6 7 8 9))
-(define column-pins (vector 11 12 18 19 10 7 8 9 5 6))
-(define layout (vector key-a key-s key-d key-f key-g
-                       key-h key-j key-k key-l key-semicolon))
+(define column-pins (list 11 12 18 19 10 7 8 9 5 6))
+(define layout (list key-a key-s key-d key-f key-g
+                     key-h key-j key-k key-l key-semicolon))
 
-(define (scan-column last n)
-  (if (low? (vector-ref column-pins n))
-      (vector-ref layout n)
-      last))
+(define (scan-column column-pins layout pressed)
+  (if (null? column-pins)
+      pressed
+      (scan-column (cdr column-pins)
+                   (cdr layout)
+                   (if (low? (car column-pins))
+                       (car layout)
+                       pressed))))
 
 (define (loop)
-  (let ((pressed (fold scan-column 0 columns)))
+  (let ((pressed (scan-row column-pins layout 0)))
     (call-c-func "usb_send" 0 pressed 0 0 0 0 0))
   (loop))
 
@@ -26,8 +29,8 @@
                              8 2 4 32 65 128))
   (output 1)
   (low 1)
-  (for-each-vector input column-pins)
-  (for-each-vector high column-pins) ; activate pullup resistors
+  (for-each input column-pins)
+  (for-each high column-pins) ; activate pullup resistors
   (call-c-func "usb_init")
   (pause 200))