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--- 12_neopixel_led_strip [2026/08/02 13:40] – [Knight Rider Lights] walkeradmin
+++ 12_neopixel_led_strip [2026/08/02 13:48] (current) – [Knight Rider Lights] walkeradmin
@@ Line 514: / Line 514: @@
     chase_bounce((255, 0, 0), 0.08)
 </code>
+So, what does this extra code do? and how?
+\\
+\\
+Here is an explanation of the reverse code block in general.
+<code:python | download>
+# Backward direction (move the lit LED from right to left)
+# range(NUM_LEDS - 2, 0, -1) generates:
+# For 12 LEDs → 10, 9, 8, 7, 6, 5, 4, 3, 2, 1
+# - Start at LED 10 (second-to-last)
+# - Stop at LED 1 (LED 0 is skipped to avoid repeating the end LED)
+# - Step backwards by -1 each time
+for i in range(NUM_LEDS - 2, 0, -1):
+    clear()              # Turn all LEDs off before lighting the next one
+    np[i] = color        # Light the current LED at position i
+    np.write()           # Send the updated LED data to the strip
+    time.sleep(delay)    # Pause so the movement is visible
+</code>
+And this is what the line that makes the count to backwards actually does.
+<code:python | download>
+range(NUM_LEDS - 2, 0, -1)
+#Breakdown for NUM_LEDS = 12:
+Start: NUM_LEDS - 2 → 10
+#(LED 11 was already lit in the forward chase)
+Stop: 0
+#(but Python stops before 0, so last value is 1)
+Step: -1
+#(count backwards)
+</code>
+For the reverse sequence, we don't need to worry about the first (0) or last (11) LEDs as these are already set by the forward sequence.
+\\
+\\
+That's it! Oh, and don't worry, I won't be fitting these to my car :)
+\\
+\\
+----