Index: aisleriot/sol.scm
===================================================================
--- aisleriot/sol.scm	(revision 5971)
+++ aisleriot/sol.scm	(working copy)
@@ -296,6 +296,17 @@
 (define (empty-slot? slot-id)
   (null? (get-cards slot-id)))
 
+(define (any-slot-empty? slots)
+  (if (eq? slots '())
+      #f
+      (or (empty-slot? (car slots))
+          (any-slot-empty? (cdr slots)))))
+
+(define (find-empty-slot slots)
+  (if (empty-slot? (car slots))
+      (car slots)
+      (find-empty-slot (cdr slots))))
+
 ; Get the nth card from a slot. Returns #f if n is out of range.
 (define (get-nth-card slot-id n)
   (let ((cards (get-cards slot-id)))
@@ -522,6 +533,12 @@
 (define (nthcdr n lst)
   (if (zero? n) lst (nthcdr (+ -1 n) (cdr lst))))
 
+; guile library function I'm not sure I can rely on
+(define (list-head lst k)
+  (if (= k 0)
+      '()
+      (cons (car lst) (list-head (cdr lst) (- k 1)))))
+
 ;; INTERNAL procedures
 
 ; global variables
Index: aisleriot/rules/spider.scm
===================================================================
--- aisleriot/rules/spider.scm	(revision 5971)
+++ aisleriot/rules/spider.scm	(working copy)
@@ -45,6 +45,8 @@
 
 (define winning-score 96)
 
+(define allow-empty-slots #f)
+
 (define (new-game)
   (initialize-playing-area)
   (make-deck)
@@ -120,7 +122,8 @@
   #t)
 
 (define (check-for-points slot)
-  (and (is-visible? (cadr (get-cards slot)))
+  (and (> (length (get-cards slot)) 1)
+       (is-visible? (cadr (get-cards slot)))
        (eq? (get-suit (get-top-card slot))
             (get-suit (cadr (get-cards slot))))
        (= (+ 1 (get-value (get-top-card slot)))
@@ -165,16 +168,11 @@
   (and (droppable? start-slot card-list end-slot)
        (complete-transaction start-slot card-list end-slot)))
 
-(define (any-slot-empty? slots)
-  (if (eq? slots '())
-      #f
-      (or (empty-slot? (car slots))
-          (any-slot-empty? (cdr slots)))))
-
 (define (button-clicked slot)
   (and (= stock slot)
        (not (empty-slot? stock))
-       (if (any-slot-empty? tableau)
+       (if (and (not allow-empty-slots)
+                (any-slot-empty? tableau))
 	   (begin
              (set-statusbar-message (_"Please fill in empty pile first."))
              #f)
@@ -183,8 +181,20 @@
 	     (give-status-message)
 	     #t))))
 
+
+(define (is-playable-stack cards n)
+  (and (not (null? cards))
+       (= (get-value (car cards)) n)
+       (or (= n 13)
+           (is-playable-stack (cdr cards) (+ n 1)))))
+
 (define (button-double-clicked slot)
-  #f)
+  (and (member slot tableau)
+       (is-playable-stack (get-cards slot) 1)
+       (let ((card-list (list-head (get-cards slot) 13)))
+            (remove-n-cards slot 13)
+            (complete-transaction slot card-list (find-empty-slot foundation)))
+       #t))
 
 (define (game-over)
   (and (not (game-won))