void setup() {
  // put your setup code here, to run once:
  // mengatur pin 13, 12, dan 11 sebagai output
pinMode(13, OUTPUT);
pinMode(12, OUTPUT);
pinMode(11, OUTPUT);
//memastikan semua led mati saat awal
digitalWrite(13, LOW);
digitalWrite(12, LOW);
digitalWrite(11, LOW);
}

void loop() {
  // put your main code here, to run repeatedly:
//menyalakan led di pin 13, mematikan yang lain
digitalWrite(13, HIGH);
digitalWrite(12, LOW);
digitalWrite(11, LOW);
delay(1000); //tunggu 1 detik

//menyalakan led di pin 12, mematikan yang lain
digitalWrite(13, LOW);
digitalWrite(12, HIGH);
digitalWrite(11, LOW);
delay(1000); //tunggu 1 detik

//menyalakan led di pin 11, mematikan yang lain
digitalWrite(13, LOW);
digitalWrite(12, LOW);
digitalWrite(11, HIGH);
delay(1000); //tunggu 1 detik
}