diff --git a/p10/p10.org b/p10/p10.org
index 474ec27..f004b88 100644
--- a/p10/p10.org
+++ b/p10/p10.org
@@ -580,7 +580,7 @@ try to split into chunks
 
   (create-chunks 3 '(a b c d e))
 
-  (defun solve-well-ordered-chunks (matrix)
+  (defun solve-well-ordered-chunks-mod (matrix prime)
     ;; we start from the last row
     (let* ((soln-acc nil)
      (number-of-buttons (1- (length (car matrix))))
@@ -604,7 +604,7 @@ try to split into chunks
             (setq soln new-soln
                   soln-chunks (append chunks-to-store soln-chunks))))
         (let* ((row (nth current-row matrix))
-               (a (car row))
+               (a (mod  (car row) prime))
                (rrow (cdr row))
                (i (--find-index (not (zerop it)) (-take last-used-button rrow))))
           (if i
@@ -612,24 +612,19 @@ try to split into chunks
                                                 (-iota (- last-used-button i) i))))
                 (if (= 1 (length possible-indices)) ;no choices here, easy
                     (setq soln (-non-nil (--map (let* ((correction (advent/dot it rrow))
-                                                       (corrected-a (- a correction)))
-                                                  (unless (< corrected-a 0)
-                                                    (-replace-at i corrected-a it)))
+                                                       (corrected-a (mod (- a correction) prime)))
+                                                  (-replace-at i corrected-a it))
                                                 soln))
-
                           last-used-button i
                           current-row (1- current-row)) ; this needs to change
                   ;;otherwise, we create a number of solutions
                   (let* ((button (-last-item possible-indices)))
-                    (setq soln (--mapcat (let* ((max-soln (-min (-non-nil (-map (lambda (row)
-                                        (when (= 1 (nth button (cdr row)))
-                                          (- (car row) (advent/dot it (cdr row)))))
-                                          matrix)))))
-                                           (unless (< max-soln 0)
-                                             (-map (lambda (candidate) (-replace-at button candidate it)) (-iota (1+ max-soln) max-soln -1))))
+                    (setq soln (--mapcat (-map (lambda (candidate)
+  					       (-replace-at button candidate it))
+  					     (-iota prime))
                                          soln)
                           last-used-button button))))
-            (setq soln (--filter (= a (advent/dot it rrow)) soln)
+            (setq soln (--filter (= (mod a prime) (mod (advent/dot it rrow) prime)) soln)
                   current-row (1- current-row)))))
       (push soln soln-acc)
       (apply #'append soln-acc)))