diff --git a/sand.flan b/sand.flan
index 60bb8ed..f683bac 100644
--- a/sand.flan
+++ b/sand.flan
@@ -25,6 +25,28 @@
 (defonce velocity [rows [cols f32]])
 (defonce current-color dyn 0)
 
+(defn insertion-sort [coll [$t]] ()
+  {:where (ordered? $t)}
+  (let [i 1
+        length (len coll)]
+    (while (and (< i length))
+      (let [j i]
+        (while (and (> j 0)
+                    (< (at coll j) (at coll (dec j))))
+          (let [temp (at coll j)]
+            (set (at coll j) (at coll (dec j)))
+            (set (at coll (dec j)) temp))
+          (-- j)))
+      (++ i))))
+
+(comment
+  (insertion-sort [\I \N \S \E \R \T \I \O \N \S \O \R \T])
+  (insertion-sort (slice [6 2 4 9 1 9 4 5] 0 8))
+  (let [str (bytes "INSERTIONSORT")]
+    (insertion-sort str)
+    (println str))
+  :-)
+
 (defn clear-grid [] ()
   (set grid     (zeroed))
   (set velocity (zeroed)))
@@ -41,7 +63,7 @@
           (when (and (>= r 0) (< r (- rows 1))
                      (>= c 0) (< c (- cols 1))
                      (= 0 (at grid r c))
-                     (< (rand-f32) 0.5))
+                     (< (f32 (rand)) 0.5))
             (set (at grid r c) (dyn->u32 (at colors current-color)))
             (set (at velocity r c) 1.0)))))))
 
@@ -61,7 +83,7 @@
           (let [side (cond
                        (not left?)  1
                        (not right?) -1
-                       :else        (if (< (rand-f32) 0.5) 1 -1))]
+                       :else        (if (< (f32 (rand)) 0.5) 1 -1))]
             (set (at grid y (+ col side))       (at grid row col))
             (set (at grid row col)              0)
             (set (at velocity y (+ col side))   vel)
diff --git a/test/test_acceptance.ml b/test/test_acceptance.ml
index 2e47da7..8af1369 100644
--- a/test/test_acceptance.ml
+++ b/test/test_acceptance.ml
@@ -2267,12 +2267,11 @@ let () =
        libraylib on every target, and this one is the version meant to run on
        wasm32 too. The hash is reproducible only because rand is ours.
 
-       The number below is the *old* generator's grid and cannot be right
-       again: a draw is 64 bits now and every grain lands somewhere else. When
-       sand.flan is brought up to date and these rows run again, the hash is
-       re-taken from the run — that is the one manual step, and it is the
-       normal one for this case. *)
-    let sand_out = "15595743031174623232\n" in
+       The number below was re-taken when the generator changed: a draw is 64
+       bits now and every grain lands somewhere else, so the old grid's hash
+       could not be right again. Re-taking it from a run is the one manual
+       step, and it is the normal one for this case. *)
+    let sand_out = "7623511701454096497\n" in
     if sand_checks then begin
       outputs "sand, headless" "programs/sand-headless.flan" sand_out;
       outputs ~opt:"-O0" "sand, headless, -O0" "programs/sand-headless.flan"