diff --git a/package.lisp b/package.lisp
index a32d8a6..5b69ba9 100644
--- a/package.lisp
+++ b/package.lisp
@@ -20,6 +20,7 @@
     :_2
     :partial-2
     :defun/memo
+    :memoizing
 
     :with-complex-parts
     :complex-rotate-cw
diff --git a/src/2023/day12.lisp b/src/2023/day12.lisp
index fe19409..7dd9571 100644
--- a/src/2023/day12.lisp
+++ b/src/2023/day12.lisp
@@ -6,18 +6,6 @@
     (list springs (extract-positive-integers groups))))
 
 
-(defmacro memoizing ((ht &rest key-parts) &body body)
-  (with-gensyms (memo key)
-    `(let ((,memo ,ht)
-           (,key (list ,@key-parts)))
-       (multiple-value-bind (res res?) (gethash ,key ,memo)
-         (if res?
-           res
-           (setf (gethash ,key ,memo)
-                 (block memo
-                        ,@body)))))))
-
-
 (defun count-valid-arrangements (s)
   (destructuring-bind (springs groups) (parse-condition-record s)
     (bnd1 (memo (make-hash-table :test 'equal))
diff --git a/src/utils.lisp b/src/utils.lisp
index c2d1b8f..d03287a 100644
--- a/src/utils.lisp
+++ b/src/utils.lisp
@@ -356,6 +356,16 @@
     `(defun ,clear-memo-name ()
       (clrhash ,memo))))
 
+(defmacro memoizing ((ht &rest key-parts) &body body)
+  (with-gensyms (memo key)
+    `(let ((,memo ,ht)
+           (,key (list ,@key-parts)))
+       (multiple-value-bind (res res?) (gethash ,key ,memo)
+         (if res?
+           res
+           (setf (gethash ,key ,memo)
+                 (block memo
+                        ,@body)))))))
 
 ;;;; Math ---------------------------------------------------------------------