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

void setup() {
  // Initialize all LED pins as outputs
  for (int i = 0; i < 7; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
}

void loop() {
  // 1st LED lights up
  digitalWrite(ledPins[0], HIGH);
  delay(1000);
  
  // 2nd and 3rd LED light up
  digitalWrite(ledPins[1], HIGH);
  digitalWrite(ledPins[2], HIGH);
  delay(1000);
  
  // 4th and 5th LED light up
  digitalWrite(ledPins[3], HIGH);
  digitalWrite(ledPins[4], HIGH);
  delay(1000);
  
  // All LED light up
  for (int i = 0; i < 7; i++) {
    digitalWrite(ledPins[i], HIGH);
  }
  delay(1000);
  
  // 6th and 7th LED power off
  digitalWrite(ledPins[5], LOW);
  digitalWrite(ledPins[6], LOW);
  delay(1000);
  
  // 4th and 5th LED power off
  digitalWrite(ledPins[3], LOW);
  digitalWrite(ledPins[4], LOW);
  delay(1000);
  
  // 3rd and 2nd LED power off
  digitalWrite(ledPins[2], LOW);
  digitalWrite(ledPins[1], LOW);
  delay(1000);
  
  // 1st LED left
  digitalWrite(ledPins[0], HIGH);
  delay(1000);
}