diff --git a/light_manager.py b/light_manager.py
index 09a1fe3..662fc6a 100644
--- a/light_manager.py
+++ b/light_manager.py
@@ -25,6 +25,9 @@ class LightStrip:
   def get_next_pattern_tick(self):
     n = self.np.n
     t = self.cur_tick
+    if not len(self.cur_pattern) >= n - 1:
+      li = [(255, 255, 255)] * (n - len(self.cur_pattern))
+      self.cur_pattern.extend(li)
     for i in range(n):
       self.cur_pattern[i] = self.pattern(i, t)
     self.cur_tick = t + 1