Chain DualKey RGB LED

#define LED_PWR_PIN 40
#define LED_SIG_PIN 21
#define NUM_LEDS 2

#include <Adafruit_NeoPixel.h>

Adafruit_NeoPixel LED(NUM_LEDS, LED_SIG_PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  pinMode(LED_PWR_PIN, OUTPUT);
  digitalWrite(LED_PWR_PIN, HIGH);

  LED.begin();
  LED.show();
}

void loop() {
  // White (all on)
  for (int i = 0; i <= NUM_LEDS; i++) { LED.setPixelColor(i, LED.Color(255, 255, 255)); }
  LED.show();
  delay(500);

  // Black (all off)
  for (int i = 0; i <= NUM_LEDS; i++) { LED.setPixelColor(i, LED.Color(0, 0, 0)); }
  LED.show();
  delay(500);

  // Red & Green
  LED.setPixelColor(0, LED.Color(255, 0, 0));
  LED.setPixelColor(1, LED.Color(0, 255, 0));
  LED.show();
  delay(500);

  // Blue & Yellow
  LED.setPixelColor(0, LED.Color(0, 0, 255));
  LED.setPixelColor(1, LED.Color(255, 255, 0));
  LED.show();
  delay(500);

  // Magenta & Cyan
  LED.setPixelColor(0, LED.Color(255, 0, 255));
  LED.setPixelColor(1, LED.Color(0, 255, 255));
  LED.show();
  delay(500);
}