diff --git a/clock/api/hat/tester.py b/clock/api/hat/tester.py
index 5f868da..6aab31b 100644
--- a/clock/api/hat/tester.py
+++ b/clock/api/hat/tester.py
@@ -6,4 +6,5 @@ for i in range(16*32):
     x = i % 32
     y = i // 32
     led.set_pixel(x,y, 10, 200, 30)
-    led.show()
\ No newline at end of file
+    if i%2 == 0:
+        led.show()
\ No newline at end of file