// Define pin numbers for LEDs
const int ledPins[] = {2, 3, 4, 5, 6}; // Pins for LEDs

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

void loop() {
  // Turn on each LED in sequence
  for (int i = 0; i < sizeof(ledPins) / sizeof(ledPins[0]); i++) {
    digitalWrite(ledPins[i], HIGH);
    delay(500); // Delay for 500 milliseconds (0.5 seconds)
  }

  // Turn off each LED in sequence
  for (int i = sizeof(ledPins) / sizeof(ledPins[0]) - 1; i >= 0; i--) {
    digitalWrite(ledPins[i], LOW);
    delay(500); // Delay for 500 milliseconds (0.5 seconds)
  }
}