diff --git a/effects.h b/effects.h
index 77efd60..8941234 100644
--- a/effects.h
+++ b/effects.h
@@ -266,3 +266,33 @@ class Animation : public Effect {
       return animation->delays[0];
     }
 };
+
+class SingleDynamic : public Effect {
+  protected:
+    static const int factor = 2;
+    static const int tile_count = LED_WIDTH/factor * LED_HEIGHT/factor;
+    CRGB tiles[tile_count];
+  public:
+    SingleDynamic() {
+      for (int i=0; i<tile_count; i++) tiles[i] = CHSV(random8(), 120, 255);
+    }
+    virtual void update() {
+      tiles[random8() % tile_count] = CHSV(random8(), 120, 255);
+    }
+    boolean can_be_shown_with_clock() { return true; }
+    void loop() {
+      EVERY_N_MILLISECONDS(400) { update(); }
+      
+      for (int x=0; x<window.w; x++) for (int y=0; y<window.h; y++) {
+        int index = y/2 * window.w/2 + x/2;
+        setPixel(window, x, y, tiles[index]);
+      }
+    }
+};
+
+class MultiDynamic : public SingleDynamic {
+  public:
+    void update() {
+      for (int i=0; i<tile_count; i++) tiles[i] = CHSV(random8(), 120, 255);
+    }
+};
diff --git a/pitrix.ino b/pitrix.ino
index 2e05734..ca7a473 100644
--- a/pitrix.ino
+++ b/pitrix.ino
@@ -34,7 +34,7 @@ typedef struct {
 #include "tools.h"
 #include "effects.h"
 
-#define NUM_EFFECTS 7
+#define NUM_EFFECTS 9
 //EffectEntry effects[NUM_EFFECTS];
 Sinematrix3 sinematrix3;
 BigClock big_clock;
@@ -43,6 +43,8 @@ Bell bell;
 Static off(CRGB(0x000000));
 Animation anim_koopa(&koopa, CRGB(0x000000), 0, 0);
 Animation anim_couple_rain(&couple_rain, CRGB(0x000000), -8, -16);
+SingleDynamic single_dynamic;
+MultiDynamic multi_dynamic;
 
 EffectEntry effects[NUM_EFFECTS] = {
   {"sinematrix3", (Effect *)&sinematrix3},
@@ -51,7 +53,9 @@ EffectEntry effects[NUM_EFFECTS] = {
   {"bell", (Effect *)&bell},
   {"off", (Effect *)&off},
   {"koopa", (Effect *)&anim_koopa},
-  {"couple_rain", (Effect *)&anim_couple_rain}
+  {"couple_rain", (Effect *)&anim_couple_rain},
+  {"single_dynamic", (Effect *)&single_dynamic},
+  {"multi_dynamic", (Effect *)&multi_dynamic}
 };