int ledPins[] = {2, 3, 4, 5, 6, 7, 8, 9}; 
int pinCount = 8; 
int timer = 1000; 
boolean isOpen = false;

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

void loop() {
  if (!isOpen) {
    // Close double curtain
    for (int i = 0; i < pinCount / 2; i++) {
      digitalWrite(ledPins[i], HIGH); 
      digitalWrite(ledPins[pinCount - i - 1], HIGH); 
      delay(timer);
    }
    isOpen = true;
  } else {
    // Open double curtain
    for (int i = pinCount / 2 - 1; i >= 0; i--) {
      digitalWrite(ledPins[i], LOW); 
      digitalWrite(ledPins[pinCount - i - 1], LOW); 
      delay(timer);
    }
    isOpen = false;
  }
  delay(1000); // Wait for 1 second before opening/closing again
}