// Define the pins for the LEDs
const int ledPins[] = {2, 3, 4, 5, 6, 7, 8, 9};

// Number of LEDs
const int numLeds = sizeof(ledPins) / sizeof(ledPins[0]);

// Define the rhythm of the song in milliseconds
// Based on the rhythm of "We Wish You a Merry Christmas and a Happy New Year"
// This is a simplified version and may not perfectly match the actual song
const int rhythm[] = {
  500, 500, 500, 500, 1000,  // "We wish you a"
  500, 500, 500, 500, 1000,  // "Merry Christmas"
  500, 500, 500, 500, 1000,  // "We wish you a"
  500, 500, 500, 500, 1000,  // "Merry Christmas"
  500, 500, 500, 500, 1000,  // "We wish you a"
  500, 500, 500, 500, 1000,  // "Merry Christmas"
  500, 500, 500, 500, 1000,  // "And a happy"
  500, 500, 500, 500, 2000   // "New Year"
};

// Number of rhythm elements
const int rhythmLength = sizeof(rhythm) / sizeof(rhythm[0]);

void setup() {
  // Initialize the LED pins as outputs
  for (int i = 0; i < numLeds; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
}

void loop() {
  // Play the rhythm of the song using the LEDs
  for (int i = 0; i < rhythmLength; i++) {
    // Turn on the current LED
    digitalWrite(ledPins[i % numLeds], HIGH);
    // Wait according to the rhythm
    delay(rhythm[i]);
    // Turn off the current LED
    digitalWrite(ledPins[i % numLeds], LOW);
  }
  
  // Wait for a short while before repeating the sequence
  delay(1000);
}