diff --git a/p10/p10.org b/p10/p10.org
index 92cbf3d..42ecb77 100644
--- a/p10/p10.org
+++ b/p10/p10.org
@@ -196,13 +196,10 @@ These are some auxiliary functions to create and deal with matrices
 | 38 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 |
 | 61 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 |
 
-
-#+RESULTS:
-|  7 | 1 | 0 | 1 | 1 | 0 |
-|  5 | 0 | 0 | 0 | 1 | 1 |
-| 12 | 1 | 1 | 0 | 1 | 1 |
-|  7 | 1 | 1 | 0 | 0 | 1 |
-|  2 | 1 | 0 | 1 | 0 | 1 |
+#+begin_src emacs-lisp
+  (setq buttons nil)
+  (solve-well-ordered (matrix-buttons (fix-machine (nth 1 machines))))
+#+end_src
 
 
 
@@ -268,6 +265,7 @@ possibility
            (current-row (1- (length matrix))))
       (while (> last-used-button 0)
         (push last-used-button buttons)
+        (message (format "%d" (length soln)))
         (let* ((row (nth current-row matrix))
                (a (car row))
                (rrow (cdr row))
@@ -290,15 +288,21 @@ possibility
                                            (if (< max-soln 0) (list it)
                                              (-map (lambda (candidate) (-replace-at button candidate it)) (-iota (1+ max-soln)))))
                                          soln)
+                          ; remove solutions that are not feasible
+                          soln (--filter (--every (>= it 0) (-map (lambda (row)
+                                                                    (let ((correction (advent/dot it (cdr row))))
+                                                                      (- (car row) correction)))
+                                                                  matrix))
+                                         soln)
                           last-used-button button))))
-            (setq soln (-non-nil (--map (when (= a (advent/dot it rrow)) it) soln))
+            (setq soln (--filter (= a (advent/dot it rrow)) soln)
                   current-row (1- current-row)))))
       soln))
 
   (defun minimal-pushes (machine)
     (-min (-map #'-sum (solve-row-reduced (row-reduce (matrix-buttons machine))))))
 
-  last-used-button
+
 #+end_src
 
 #+RESULTS: