const int ledcount = 8;
int leds[ledcount] = {2,3,4,5,6,7,8,9};

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

void loop() {
  //dari kanan ke kiri
  for (int i = ledcount - 1; i >= 0; i--){
    digitalWrite(leds[i] , HIGH);
    delay(200);
    digitalWrite(leds[i], LOW);
}

//dari kiri kekanan
for (int i = 0; i < ledcount; i++){
  digitalWrite(leds[i], HIGH);
  delay(200);
  digitalWrite(leds[i], LOW);
}
}