diff --git a/effects.h b/effects.h
index b943c7a..c5df912 100644
--- a/effects.h
+++ b/effects.h
@@ -413,3 +413,19 @@ class CycleEffect : public Effect {
       }
     }
 };
+
+class TwirlEffect : public Effect {
+  private:
+    uint8_t angleOffset = 0;
+    double center_x = 8;
+    double center_y = 8;
+  public:
+    void loop() {
+      for (int x=0; x<window.w; x++) for (int y=0; y<window.h; y++) {
+        uint8_t angle = (x==center_x && y==center_y) ? 0 : atan2(y - center_y, x - center_x) / M_PI * 128 + 128 + angleOffset;
+        uint8_t brightness = sqrt16((center_x - x) * (center_x - x) + (center_y - y) * (center_y - y)) & 0xFF;
+        setPixel(window, x, y, CHSV(angle, (brightness<<5) & 0xFF, 255));
+      }
+      angleOffset += 1;
+    }
+};
diff --git a/pitrix.ino b/pitrix.ino
index 3855fba..77b3401 100644
--- a/pitrix.ino
+++ b/pitrix.ino
@@ -53,7 +53,7 @@ SimpleList<Effect*>* cycle_effects;
 
 #include "effects.h"
 
-#define NUM_EFFECTS 11
+#define NUM_EFFECTS 12
 //EffectEntry effects[NUM_EFFECTS];
 Sinematrix3 sinematrix3;
 BigClock big_clock;
@@ -66,6 +66,7 @@ SingleDynamic single_dynamic;
 MultiDynamic multi_dynamic;
 MatrixEffect matrix;
 CycleEffect effect_cycle;
+TwirlEffect effect_twirl;
 
 EffectEntry effects[NUM_EFFECTS] = {
   {"sinematrix3", (Effect *)&sinematrix3},
@@ -79,6 +80,7 @@ EffectEntry effects[NUM_EFFECTS] = {
   {"multi_dynamic", (Effect *)&multi_dynamic},
   {"matrix", (Effect *)&matrix},
   {"cycle", (Effect *)&effect_cycle},
+  {"twirl", (Effect *)&effect_twirl},
 };
 
 void setup_cycle_effects() {