int ledPins[] = {2, 3, 4, 5, 6};  // Pin numbers for the 5 LEDs
int numLeds = 5;

void setup() {
  for (int i = 0; i < numLeds; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
}

void loop() {
  // Turn on LEDs one by one
  for (int i = 0; i < numLeds; i++) {
    digitalWrite(ledPins[i], HIGH);
    delay(100);  // Each LED stays on for 200 ms
    digitalWrite(ledPins[i], LOW);
  }
  
  // Optional: Reverse direction (makes the lights run back)
  for (int i = numLeds - 1; i >= 0; i--) {
    digitalWrite(ledPins[i], HIGH);
    delay(100);
    digitalWrite(ledPins[i], LOW);
  }
}