void setup() {
  // put your setup code here, to run once:
for(int x=2; x<=13; x++){pinMode(x, OUTPUT);}
}

void loop() {
  // lampu led menyala dari kanan ke kiri
for (int x=2; x<=13; x++){
  digitalWrite(x, HIGH);
  delay(100);
  digitalWrite(x, LOW);}

  // lampu led menyala dari kiri ke kanan
  for(int x=13; x>=2; x--){
    digitalWrite(x, HIGH);
    delay(80);
    digitalWrite(x, LOW);
  }
}