diff --git a/collects/games/same/same-lib.rkt b/collects/games/same/same-lib.rkt
new file mode 100644
index 0000000000..76aaa06bc9
--- /dev/null
+++ b/collects/games/same/same-lib.rkt
@@ -0,0 +1,226 @@
+#lang racket/base
+(require racket/class
+         racket/gui/base)
+
+(provide make-a-move
+         
+         draw-board
+         update-pen/draw-blob
+         update-dc-scale
+         
+         colors
+         board-ref
+         cell-w
+         cell-h
+         find-same-colors)
+
+;; these are the sizes that the on-paint callback draws at;
+;; a scaling factor is applied to make the board fit the window
+(define cell-w 11)
+(define cell-h 11)
+(define pen-size 10)
+
+(define colors (map (lambda (x) (make-object color% x))
+                    (list "blue" "red" "brown" "forestgreen" "purple")))
+(define pale-colors 
+  (for/list ([x (in-list colors)])
+    (define (paleize x) (- 255 (floor (* (- 255 x) 2/3))))
+    (make-object color%
+      (paleize (send x red))
+      (paleize (send x green))
+      (paleize (send x blue)))))
+
+(define (draw-board dc board-width board-height board cw ch
+                    mouse-current-x mouse-current-y mouse-clicked-x mouse-clicked-y)
+  (send dc erase) 
+  (send dc set-smoothing 'smoothed)
+  (update-dc-scale dc cw ch board-width board-height)
+  (define painted (make-hash))
+  (for* ([i (in-range 0 board-width)]
+         [j (in-range 0 board-height)])
+    (unless (hash-ref painted (xy->key board-width i j) #f)
+      (define color (vector-ref (board-ref board i j) 0))
+      (when color
+        (define blob (find-same-colors board board-width board-height i j))
+        (for ([x (in-list blob)])
+          (hash-set! painted (xy->key board-width (blob-sel-x x) (blob-sel-y x)) #t))
+        (update-pen/draw-blob
+         blob dc color
+         mouse-current-x mouse-current-y mouse-clicked-x mouse-clicked-y)))))
+
+(define (update-dc-scale dc cw ch board-width board-height)
+  (send dc set-scale 
+        (/ cw (* board-width cell-w)) 
+        (/ ch (* board-height cell-h))))
+
+(define (update-pen/draw-blob
+         blob dc color
+         mouse-current-x mouse-current-y mouse-clicked-x mouse-clicked-y)
+  (define mouse-over? #f)
+  (define mouse-clicked-over? #f)
+  (define multiple-cells? (not (or (null? blob) (null? (cdr blob)))))
+  
+  (when (or (number? mouse-current-x)
+            (number? mouse-clicked-x))
+    (for ([obj (in-list blob)])
+      (define x (blob-sel-x obj))
+      (define y (blob-sel-y obj))
+      (when (and (equal? x mouse-current-x)
+                 (equal? y mouse-current-y))
+        (set! mouse-over? #t))
+      (when (and (equal? x mouse-clicked-x)
+                 (equal? y mouse-clicked-y))
+        (set! mouse-clicked-over? #t))))
+  
+  (cond
+    [mouse-clicked-x ;; has the mouse been clicked in a clickable place?
+     (cond 
+       [(and mouse-over? mouse-clicked-over? multiple-cells?)
+        (send dc set-pen (list-ref pale-colors color) (* pen-size 2/3) 'solid)
+        (draw-blob dc blob)]
+       [else
+        (send dc set-pen
+              (list-ref colors color)
+              pen-size
+              'solid)
+        (draw-blob dc blob)])]
+    [else
+     (cond
+       [mouse-over?
+        (send dc set-pen (list-ref pale-colors color) pen-size 'solid)
+        (draw-blob dc blob)]
+       [else
+        (send dc set-pen (list-ref colors color) pen-size 'solid)
+        (draw-blob dc blob)])]))
+
+(define (draw-blob dc blob)
+  (define (connect x1 y1 x2 y2)
+    (send dc draw-line 
+          (+ (/ cell-w 2) (* x1 cell-w))
+          (+ (/ cell-h 2) (* y1 cell-h))
+          (+ (/ cell-w 2) (* x2 cell-w))
+          (+ (/ cell-h 2) (* y2 cell-h))))
+  (cond
+    [(null? (cdr blob))
+     (define pt (car blob))
+     (connect (blob-sel-x pt) (blob-sel-y pt) (blob-sel-x pt) (blob-sel-y pt))]
+    [else
+     (for* ([b1 (in-list blob)]
+            [b2 (in-list blob)])
+       (when (= (+ (abs (- (blob-sel-x b1) (blob-sel-x b2)))
+                   (abs (- (blob-sel-y b1) (blob-sel-y b2))))
+                1)
+         (connect (blob-sel-x b1) (blob-sel-y b1) (blob-sel-x b2) (blob-sel-y b2))))]))
+
+(define (xy->key board-width x y) (+ (* board-width y) x))
+
+(define (make-same-bitmap pth)
+  (define bw 32)
+  (define bh 32)
+  (define bitmap (make-bitmap bw bh))
+  (define bdc (make-object bitmap-dc% bitmap))
+  (define board-width 3)
+  (define board-height 3)
+  (define board 
+    (vector (vector (vector 0 #f) (vector 1 #f) (vector 4 #f))
+            (vector (vector 0 #f) (vector 1 #f) (vector 1 #f))
+            (vector (vector 3 #f) (vector 3 #f) (vector 2 #f))))
+  (draw-board bdc board-width board-height board bw bh
+              #f #f #f #f)
+  (send bdc set-bitmap #f)
+  (send bitmap save-file pth 'png))
+  
+; (make-same-bitmap "same.png")
+
+;; make-a-move : num num board num num -> num or #f
+;; mutates 'board' to reflect removing the blob at (i,j)
+;; result is the size of the removed blob, or #f if nothing got removed
+(define (make-a-move i j board board-width board-height)
+  (let ([same-colors (find-same-colors board board-width board-height i j)])
+    (cond
+      [(< (length same-colors) 2)
+       #f]
+      [else
+       
+       ;; slide down empty pieces
+       (let ([is null])
+         (for-each
+          (lambda (p)
+            (let ([i (blob-sel-x p)]
+                  [j (blob-sel-y p)])
+              (unless (member i is)
+                (set! is (cons i is)))
+              (let loop ([x j])
+                (cond
+                  [(<= 1 x)
+                   (let ([next (board-ref board i (- x 1))]
+                         [this (board-ref board i x)])
+                     (vector-set! this 0 (vector-ref next 0))
+                     (loop (- x 1)))]
+                  [else
+                   (vector-set! (board-ref board i x) 0 #f)]))))
+          (sort same-colors
+                (lambda (x y) (<= (blob-sel-y x) (blob-sel-y y)))))
+         
+         ;; slide empty over empty rows
+         (set! is (sort is >))
+         (let ([empty-is 
+                (filter (lambda (i)
+                          (not (vector-ref 
+                                (board-ref board i (- board-height 1))
+                                0)))
+                        is)])
+           (let ([is (if (null? empty-is)
+                         is
+                         (filter (lambda (x) (< x (car empty-is)))
+                                 is))])
+             (for-each (lambda (empty-i)
+                         (let loop ([i empty-i])
+                           (cond
+                             [(<= i (- board-width 2))
+                              (vector-set! board i (vector-ref board (+ i 1)))
+                              (loop (+ i 1))]
+                             [(= i (- board-width 1))
+                              (vector-set! 
+                               board
+                               i
+                               (build-vector board-height
+                                             (λ (i) (vector #f #f))))])))
+                       empty-is))))
+       
+       (length same-colors)])))
+
+(define (blob-sel-x b) (vector-ref b 1))
+(define (blob-sel-y b) (vector-ref b 2))
+(define (board-ref b x y) (vector-ref (vector-ref b x) y))
+
+(define (find-same-colors board board-width board-height i j)
+  (let* ([index (vector-ref (board-ref board i j) 0)]
+         [ans
+          (let loop ([i i]
+                     [j j]
+                     [ps null])
+            (cond
+              [(not (and (<= 0 i) (< i board-width)
+                         (<= 0 j) (< j board-height)))
+               ps]
+              [else
+               (let ([v (board-ref board i j)])
+                 (cond 
+                   [(vector-ref v 1) ps]
+                   [(not (vector-ref v 0)) ps]
+                   [(= index (vector-ref v 0))
+                    (vector-set! v 1 #t)
+                    (loop (+ i 1)
+                          j
+                          (loop (- i 1)
+                                j
+                                (loop i
+                                      (- j 1)
+                                      (loop i
+                                            (+ j 1)
+                                            (cons (vector v i j)
+                                                  ps)))))]
+                   [else ps]))]))])
+    (for-each (lambda (p) (vector-set! (vector-ref p 0) 1 #f)) ans)
+    ans))
diff --git a/collects/games/same/same.rkt b/collects/games/same/same.rkt
index 710113ec87..f620fd9e66 100644
--- a/collects/games/same/same.rkt
+++ b/collects/games/same/same.rkt
@@ -4,7 +4,8 @@
          racket/list
          racket/gui/base
          racket/math
-         "../show-scribbling.ss")
+         "../show-scribbling.ss"
+         "same-lib.rkt")
 
 (provide game@)
 
@@ -149,7 +150,11 @@
                (update-pen/draw-blob
                 blob dc color
                 mouse-current-x mouse-current-y
-                mouse-clicked-x mouse-clicked-y))]))
+                mouse-clicked-x mouse-clicked-y))])
+          
+          (when game-over?
+            (update-dc-scale dc cw ch board-width board-height)
+            (paint-game-over)))
         
         (define/private (build-background)
           (unless background-valid?
@@ -198,9 +203,14 @@
           (when (send evt button-up?)
             (when (and (equal? mouse-clicked-x bx)
                        (equal? mouse-clicked-y by))
-              (make-a-move)
-              (update-game-over)
-              (refresh)))
+              (define removed-ball-count
+                (make-a-move mouse-clicked-x mouse-clicked-y 
+                             board board-width board-height))
+              (when removed-ball-count
+                (update-score removed-ball-count)
+                (invalidate-board-bitmap)
+                (update-game-over)
+                (refresh))))
           
           (define-values (new-mouse-clicked-x new-mouse-clicked-y)
             (cond
@@ -244,64 +254,6 @@
                        ""
                        (format "~a" (calc-score num)))]
                   [else ""])))
-          
-        (define/private (make-a-move)
-          (define i mouse-clicked-x)
-          (define j mouse-clicked-y)
-          (invalidate-board-bitmap)
-          (let ([same-colors (find-same-colors board board-width board-height i j)])
-            
-            (when (>= (length same-colors) 2)
-              
-              ;; slide down empty pieces
-              (let ([is null])
-                (for-each
-                 (lambda (p)
-                   (let ([i (blob-sel-x p)]
-                         [j (blob-sel-y p)])
-                     (unless (member i is)
-                       (set! is (cons i is)))
-                     (let loop ([x j])
-                       (cond
-                         [(<= 1 x)
-                          (let ([next (board-ref board i (- x 1))]
-                                [this (board-ref board i x)])
-                            (vector-set! this 0 (vector-ref next 0))
-                            (loop (- x 1)))]
-                         [else
-                          (vector-set! (board-ref board i x) 0 #f)]))))
-                 (sort same-colors
-                       (lambda (x y) (<= (blob-sel-y x) (blob-sel-y y)))))
-                
-                ;; slide empty over empty rows
-                (set! is (sort is >))
-                (let ([empty-is 
-                       (filter (lambda (i)
-                                 (not (vector-ref 
-                                       (board-ref board i (- board-height 1))
-                                       0)))
-                               is)])
-                  (let ([is (if (null? empty-is)
-                              is
-                              (filter (lambda (x) (< x (car empty-is)))
-                                      is))])
-                    (for-each (lambda (empty-i)
-                                (let loop ([i empty-i])
-                                  (cond
-                                    [(<= i (- board-width 2))
-                                     (vector-set! board i (vector-ref board (+ i 1)))
-                                     (loop (+ i 1))]
-                                    [(= i (- board-width 1))
-                                     (vector-set! 
-                                      board
-                                      i
-                                      (build-vector board-height
-                                                    (λ (i) (vector #f #f))))])))
-                              empty-is))))
-              
-              
-              ;; tally disappearing balls
-              (update-score (length same-colors)))))
         
         (define/public-final (update-game-over)
           (set! game-over?
@@ -382,158 +334,5 @@
     (send frame show #t)
     (void (yield semaphore))))
 
-;; these are the sizes that the on-paint callback draws at;
-;; a scaling factor is applied to make the board fit the window
-(define cell-w 11)
-(define cell-h 11)
-(define pen-size 10)
-
-(define colors (map (lambda (x) (make-object color% x))
-                    (list "blue" "red" "brown" "forestgreen" "purple")))
-(define pale-colors 
-  (for/list ([x (in-list colors)])
-    (define (paleize x) (- 255 (floor (* (- 255 x) 2/3))))
-    (make-object color%
-      (paleize (send x red))
-      (paleize (send x green))
-      (paleize (send x blue)))))
-
-(define (draw-board dc board-width board-height board cw ch
-                    mouse-current-x mouse-current-y mouse-clicked-x mouse-clicked-y)
-  (send dc erase) 
-  (send dc set-smoothing 'smoothed)
-  (update-dc-scale dc cw ch board-width board-height)
-  (define painted (make-hash))
-  (for* ([i (in-range 0 board-width)]
-         [j (in-range 0 board-height)])
-    (unless (hash-ref painted (xy->key board-width i j) #f)
-      (define color (vector-ref (board-ref board i j) 0))
-      (when color
-        (define blob (find-same-colors board board-width board-height i j))
-        (for ([x (in-list blob)])
-          (hash-set! painted (xy->key board-width (blob-sel-x x) (blob-sel-y x)) #t))
-        (update-pen/draw-blob
-         blob dc color
-         mouse-current-x mouse-current-y mouse-clicked-x mouse-clicked-y)))))
-
-(define (update-dc-scale dc cw ch board-width board-height)
-  (send dc set-scale 
-        (/ cw (* board-width cell-w)) 
-        (/ ch (* board-height cell-h))))
-
-(define (update-pen/draw-blob
-         blob dc color
-         mouse-current-x mouse-current-y mouse-clicked-x mouse-clicked-y)
-  (define mouse-over? #f)
-  (define mouse-clicked-over? #f)
-  (define multiple-cells? (not (or (null? blob) (null? (cdr blob)))))
-  
-  (when (or (number? mouse-current-x)
-            (number? mouse-clicked-x))
-    (for ([obj (in-list blob)])
-      (define x (blob-sel-x obj))
-      (define y (blob-sel-y obj))
-      (when (and (equal? x mouse-current-x)
-                 (equal? y mouse-current-y))
-        (set! mouse-over? #t))
-      (when (and (equal? x mouse-clicked-x)
-                 (equal? y mouse-clicked-y))
-        (set! mouse-clicked-over? #t))))
-  
-  (cond
-    [mouse-clicked-x ;; has the mouse been clicked in a clickable place?
-     (cond 
-       [(and mouse-over? mouse-clicked-over? multiple-cells?)
-        (send dc set-pen (list-ref pale-colors color) (* pen-size 2/3) 'solid)
-        (draw-blob dc blob)]
-       [else
-        (send dc set-pen
-              (list-ref colors color)
-              pen-size
-              'solid)
-        (draw-blob dc blob)])]
-    [else
-     (cond
-       [mouse-over?
-        (send dc set-pen (list-ref pale-colors color) pen-size 'solid)
-        (draw-blob dc blob)]
-       [else
-        (send dc set-pen (list-ref colors color) pen-size 'solid)
-        (draw-blob dc blob)])]))
-
-(define (draw-blob dc blob)
-  (define (connect x1 y1 x2 y2)
-    (send dc draw-line 
-          (+ (/ cell-w 2) (* x1 cell-w))
-          (+ (/ cell-h 2) (* y1 cell-h))
-          (+ (/ cell-w 2) (* x2 cell-w))
-          (+ (/ cell-h 2) (* y2 cell-h))))
-  (cond
-    [(null? (cdr blob))
-     (define pt (car blob))
-     (connect (blob-sel-x pt) (blob-sel-y pt) (blob-sel-x pt) (blob-sel-y pt))]
-    [else
-     (for* ([b1 (in-list blob)]
-            [b2 (in-list blob)])
-       (when (= (+ (abs (- (blob-sel-x b1) (blob-sel-x b2)))
-                   (abs (- (blob-sel-y b1) (blob-sel-y b2))))
-                1)
-         (connect (blob-sel-x b1) (blob-sel-y b1) (blob-sel-x b2) (blob-sel-y b2))))]))
-
-(define (xy->key board-width x y) (+ (* board-width y) x))
-
-(define (find-same-colors board board-width board-height i j)
-  (let* ([index (vector-ref (board-ref board i j) 0)]
-         [ans
-          (let loop ([i i]
-                     [j j]
-                     [ps null])
-            (cond
-              [(not (and (<= 0 i) (< i board-width)
-                         (<= 0 j) (< j board-height)))
-               ps]
-              [else
-               (let ([v (board-ref board i j)])
-                 (cond 
-                   [(vector-ref v 1) ps]
-                   [(not (vector-ref v 0)) ps]
-                   [(= index (vector-ref v 0))
-                    (vector-set! v 1 #t)
-                    (loop (+ i 1)
-                          j
-                          (loop (- i 1)
-                                j
-                                (loop i
-                                      (- j 1)
-                                      (loop i
-                                            (+ j 1)
-                                            (cons (vector v i j)
-                                                  ps)))))]
-                   [else ps]))]))])
-    (for-each (lambda (p) (vector-set! (vector-ref p 0) 1 #f)) ans)
-    ans))
-
-(define (blob-sel-x b) (vector-ref b 1))
-(define (blob-sel-y b) (vector-ref b 2))
-
-(define (board-ref b x y) (vector-ref (vector-ref b x) y))
-
-(define (make-same-bitmap pth)
-  (define bw 32)
-  (define bh 32)
-  (define bitmap (make-bitmap bw bh))
-  (define bdc (make-object bitmap-dc% bitmap))
-  (define board-width 3)
-  (define board-height 3)
-  (define board 
-    (vector (vector (vector 0 #f) (vector 1 #f) (vector 4 #f))
-            (vector (vector 0 #f) (vector 1 #f) (vector 1 #f))
-            (vector (vector 3 #f) (vector 3 #f) (vector 2 #f))))
-  (draw-board bdc board-width board-height board bw bh
-              #f #f #f #f)
-  (send bdc set-bitmap #f)
-  (send bitmap save-file pth 'png))
-  
 ; (make-same-bitmap "same.png")
 
-(invoke-unit game@)
\ No newline at end of file
diff --git a/collects/games/scribblings/same.scrbl b/collects/games/scribblings/same.scrbl
index 10bb546e27..1e1879816f 100644
--- a/collects/games/scribblings/same.scrbl
+++ b/collects/games/scribblings/same.scrbl
@@ -1,5 +1,8 @@
 #lang scribble/doc
-@(require "common.ss")
+@(require "common.ss"
+          racket/class
+          racket/draw
+          "../same/same-lib.rkt")
 
 @gametitle["Same" "same" "Dot-Removing Game"]
 
@@ -11,6 +14,30 @@ new blobs as pieces of the old blobs fall down to fill in the empty space.
 If an entire column is wiped out, all of the blobs from the
 right will slide left to take up the empty column's space.
 
+As an example, imagine a fragment of the board looked like this:
+
+@(let ()
+   (define w 100)
+   (define h 100)
+   (define bm (make-bitmap w h))
+   (define bdc (make-object bitmap-dc% bm))
+   (define board-width 6)
+   (define board-height 4)
+   (define board 
+     (build-vector
+      board-width
+      (lambda (i)
+        (build-vector
+         board-height
+         (lambda (j)
+           (vector
+            (modulo (+ i j) 3)
+            #f))))))
+   (draw-board bdc board-width board-height board w h
+               #f #f #f #f)
+   (send bdc set-bitmap #f)
+   bm)
+
 Your score increases for each ball removed from the board, in two ways.
 First, when you remove a blob, you get as many points as the square of the number
 of cells the blob occupied, so removing bigger blobs is better. Second, if there