diff --git a/src/vybe/c.clj b/src/vybe/c.clj
index 156be38e..3f0cf140 100644
--- a/src/vybe/c.clj
+++ b/src/vybe/c.clj
@@ -964,7 +964,13 @@ signal(SIGSEGV, sighandler);
                                                            first)
                      binding-sym2 (symbol (->name binding-sym))]
                  (format "for (int %s = 0; %s < %s; ++%s) {\n  %s;\n}"
-                         binding-sym2 binding-sym2 (symbol (->name range-arg)) binding-sym2
+                         binding-sym2 binding-sym2
+                         (if (symbol? range-arg)
+                           (symbol (->name range-arg))
+                           (emit (analyze range-arg
+                                          (-> (ana/empty-env)
+                                              (update :locals merge (:locals env))))))
+                         binding-sym2
                          (or (some->> (-> (cons 'do body)
                                           (analyze
                                            (-> (ana/empty-env)
@@ -1739,6 +1745,7 @@ long long int: \"long long int\", unsigned long long int: \"unsigned long long i
                       (vp/as data c))
                      c]))
         datafied (core-p/datafy res)]
+    (pp/pprint datafied)
 
     (tap> (with-meta
             [:div {:style {:color "#999999ff"
@@ -1905,7 +1912,7 @@ long long int: \"long long int\", unsigned long long int: \"unsigned long long i
 (defmethod c-invoke #'vp/as
   [{:keys [args]}]
   (format "(%s)%s"
-          (-adapt-type (:val (second args)))
+          (-adapt-type (:form (second args)))
           (emit (first args))))
 
 (defmethod c-macroexpand #'vp/arr
diff --git a/src/vybe/flecs.clj b/src/vybe/flecs.clj
index 34064aec..d8da1b34 100644
--- a/src/vybe/flecs.clj
+++ b/src/vybe/flecs.clj
@@ -688,7 +688,9 @@
                   (str/replace #"\." "_"))))
   Long
   (vybe-name [v]
-    (str "#" (unchecked-int v)))
+    (str "#" (-> (unchecked-int v)
+                 (bit-shift-left 32)
+                 (unsigned-bit-shift-right 32))))
 
   clojure.lang.Keyword
   (vybe-name [k]
diff --git a/src/vybe/type.clj b/src/vybe/type.clj
index bc521f43..8524d7f7 100644
--- a/src/vybe/type.clj
+++ b/src/vybe/type.clj
@@ -197,4 +197,5 @@
 (vp/update-aliases!
  {'Vector2 Vector2
   'Vector3 Vector3
-  'Vector4 Vector4})
+  'Vector4 Vector4
+  'Matrix Transform})
diff --git a/test/vybe/c_test.clj b/test/vybe/c_test.clj
index a3645d94..aff9c065 100644
--- a/test/vybe/c_test.clj
+++ b/test/vybe/c_test.clj
@@ -181,8 +181,8 @@
          {:ctor some-mem?
           :dtor some-mem?
           :next some-mem?}
-         (into {} (myplugin ""))))
-)
+         (into {} (myplugin "")))))
+
   (testing "Can convert a mem segment into a VybeCFn and call it as a normal function"
     (let [simple-2 (-> (:ctor (myplugin-simple ""))
                        (vc/p->fn simple))]
diff --git a/test/vybe/flecs_test.clj b/test/vybe/flecs_test.clj
index a0cf8dad..9e2ea8cf 100644
--- a/test/vybe/flecs_test.clj
+++ b/test/vybe/flecs_test.clj
@@ -4,6 +4,7 @@
    [clojure.test :refer [deftest testing is use-fixtures]]
    [vybe.flecs :as vf]
    [vybe.flecs.c :as vf.c]
+   [vybe.raylib.c :as vr.c]
    [clojure.edn :as edn]
    [vybe.panama :as vp]
    [vybe.type :as vt]
@@ -90,39 +91,98 @@
                ["alice" {:x 10.0, :y 20.0}]}
              (set @*acc))))))
 
-(vc/defn* vybe-transform :- :void
-  [it :- vf/iter_t])
-
-(vc/defn* ^:debug default-systems :- :void
-  [^:mut w :- :*]
-  (let [e (vf.c/ecs-entity-init w #vp/& (vf/entity_desc_t
+(defmacro field
+  [it c idx]
+  `(-> (vf.c/ecs-field-w-size ~it (vp/sizeof ~c) ~idx)
+       (vp/as [:* ~c])))
+
+(vc/defn* matrix-transform :- vt/Transform
+  [translation :- vt/Translation
+   rotation :- vt/Rotation
+   scale :- vt/Scale]
+  (let [mat-scale (vr.c/matrix-scale (:x scale) (:y scale) (:z scale))
+        mat-rotation (vr.c/quaternion-to-matrix @(vp/as (vp/& rotation) [:* vt/Vector4]))
+        mat-translation (vr.c/matrix-translate (:x translation) (:y translation) (:z translation))]
+    (vr.c/matrix-multiply (vr.c/matrix-multiply mat-scale mat-rotation) mat-translation)))
+
+(vc/defn* ^:debug vybe-transform :- :void
+  [it :- [:* vf/iter_t]]
+  (let [pos (field it vt/Translation 0)
+        rot (field it vt/Rotation 1)
+        scale (field it vt/Scale 2)
+
+        transform-global (field it vt/Transform 3)
+        transform-local (field it vt/Transform 4)
+
+        is-parent-set (vf.c/ecs-field-is-set it 5)
+        transform-parent (field it vt/Transform 5)]
+
+    (doseq [i (range (:count @it))]
+      (let [t-global (vp/& (nth transform-global i))
+            t-local (vp/& (nth transform-local i))
+            local (matrix-transform (nth pos i) (nth rot i) (nth scale i))]
+        (reset! @t-local local)
+        (if is-parent-set
+          (reset! @t-global (vr.c/matrix-multiply local (nth transform-parent 0)))
+          (reset! @t-global local))))))
+
+(vc/defn* default-systems :- :void
+  [w :- :*]
+  (let [e (vf.c/ecs-entity-init w (vp/& (vf/entity_desc_t
                                          {:name "vybe_transform"
                                           :add (-> [(vf.c/vybe-pair (flecs/EcsDependsOn)
                                                                     (flecs/EcsOnUpdate))]
-                                                   (vp/arr :long))}))]
-    (vf.c/ecs-system-init
-     w #vp/& (vf/system_desc_t
-              {:entity e
-               :callback #'vybe-transform
-               :query {:terms [{:first {:name (name vt/Translation)} :inout (flecs/EcsIn)}
-                               {:first {:name (name vt/Rotation)} :inout (flecs/EcsIn)}
-                               {:first {:name (name vt/Scale)} :inout (flecs/EcsIn)}
-                               {:first {:name (name vt/Transform)}
-                                :second {:name "global"}
-                                :inout (flecs/EcsOut)}
-                               {:first {:name (name vt/Transform)}
-                                :inout (flecs/EcsOut)}
-                               {:first {:name (name vt/Transform)}
-                                :second {:name "global"}
-                                :src {:id (bit-or (flecs/EcsCascade) (flecs/EcsUp))}
-                                :inout (flecs/EcsOut)
-                                :oper (flecs/EcsOptional)}]}
-               #_ #_:callback (-system-callback
-                               (fn [it-p]
-                                 (let [it (vp/jx-p->map it-p ecs_iter_t)
-                                       f-idx (mapv (fn [f] (f it)) f-arr)]
-                                   (doseq [idx (range (ecs_iter_t/count it-p))]
-                                     (each-handler (mapv (fn [f] (f idx)) f-idx))))))}))))
+                                                   (vp/arr :long))})))]
+    (tap> (vf.c/ecs-system-init
+           w (vp/& (vf/system_desc_t
+                    {:entity e
+                     :callback #'vybe-transform
+                     :query {:terms [{:first {:name (name vt/Translation)} :inout (flecs/EcsIn)}
+                                     {:first {:name (name vt/Rotation)} :inout (flecs/EcsIn)}
+                                     {:first {:name (name vt/Scale)} :inout (flecs/EcsIn)}
+                                     {:first {:name (name vt/Transform)}
+                                      :second {:name "global"}
+                                      :inout (flecs/EcsOut)}
+                                     {:first {:name (name vt/Transform)}
+                                      :inout (flecs/EcsOut)}
+                                     {:first {:name (name vt/Transform)}
+                                      :second {:name "global"}
+                                      :src {:id (bit-or (flecs/EcsCascade) (flecs/EcsUp))}
+                                      :inout (flecs/EcsOut)
+                                      :oper (flecs/EcsOptional)}]}}))))))
+
+(deftest default-systems-test
+  (let [w (vf/make-world)]
+    (vf/eid w vt/Translation)
+    (vf/eid w vt/Rotation)
+    (vf/eid w vt/Scale)
+    (vf/eid w vt/Transform)
+    (vf/eid w :global)
+    (default-systems w)
+
+    (merge w {:alice [(vt/Scale [1.0 1.0 1.0]) (vt/Translation)
+                      (vt/Rotation [0 0 0 1]) [(vt/Transform) :global] (vt/Transform)
+
+                      {:bob [(vt/Scale [1.0 1.0 1.0]) (vt/Translation)
+                             (vt/Rotation [0 0 0 1]) [(vt/Transform) :global] (vt/Transform)]}]})
+
+    (assoc w (vf/path [:alice :bob]) (vt/Translation {:x 20 :y 30}))
+    (vf/progress w)
+
+    (is (= {:m12 20.0
+            :m13 30.0
+            :m15 1.0}
+           (select-keys (get (w (vf/path [:alice :bob])) [vt/Transform :global])
+                        [:m12 :m13 :m15])))
+
+    (assoc w :alice (vt/Translation {:x 3 :y 4}))
+    (vf/progress w)
+
+    (is (= {:m12 23.0
+            :m13 34.0
+            :m15 1.0}
+           (select-keys (get (w (vf/path [:alice :bob])) [vt/Transform :global])
+                        [:m12 :m13 :m15])))))
 
 ;; Based on https://github.com/SanderMertens/flecs/blob/master/examples/c/entities/basics/src/main.c
 (deftest ex-1-w-map
@@ -131,14 +191,6 @@
     #_(def w (vf/make-world))
     #_(def w w)
 
-    #_(do
-        (vf/eid w vt/Translation)
-        (vf/eid w vt/Rotation)
-        (vf/eid w vt/Scale)
-        (vf/eid w vt/Transform)
-        (vf/eid w :global)
-        (vf.c/vybe-default-systems-c w))
-
     ;; Create a observer.
     (vf/with-observer w [:vf/name :ex-1-observer
                          :vf/events #{:set}
diff --git a/todo.md b/todo.md
index cae4040e..5d64a64c 100644
--- a/todo.md
+++ b/todo.md
@@ -253,6 +253,9 @@
   - [ ] move existing system into VybeC from C
     - [ ] direct translation
     - [ ] with-system working in VybeC
+      - [ ] set components automatically
+    - [ ] fix string tap
+    - [ ] make `@, vp/&` etc better
     - [ ] `defsystem`?
   - [ ] read from source if some function has a inline (or not) metadata telling
         us the fn spec
@@ -265,6 +268,8 @@
   - [ ] exe mode
     - [ ] check that we don't have unitialized resources in the init function if
           in this mode
+  - [ ] use generics for a `vp/mem` equivalent in VybeC
+  - [ ] share `matrix-transform` code
 - [ ] interior light
   - [ ] point light
 - [ ] multiple worlds, render twice?