diff --git a/sand.flan b/sand.flan
index f683bac..f5f48b6 100644
--- a/sand.flan
+++ b/sand.flan
@@ -28,7 +28,7 @@
 (defn insertion-sort [coll [$t]] ()
   {:where (ordered? $t)}
   (let [i 1
-        length (len coll)]
+        length (length coll)]
     (while (and (< i length))
       (let [j i]
         (while (and (> j 0)
@@ -52,7 +52,7 @@
   (set velocity (zeroed)))
 
 (defn next-color [] ()
-  (set current-color (% (+ current-color 1) (len colors))))
+  (set current-color (% (+ current-color 1) (length colors))))
 
 (defn paint-at [row i32  col i32] ()
   (let [half (/ brush-size 2)]