void setup() {
  //progam ini berfungsi sebagai inisialisasi
 //LED pin menggunakan pin 2,3 dan 4
for(int LED = 2; LED <= 4 ; LED++){
pinMode(LED, OUTPUT);
}
}
void loop() {
  // put your main code here, to run repeatedly 
  for (int LED = 2; LED <= 4; LED++){
  digitalWrite(LED, HIGH);
  delay(200);
  digitalWrite(LED,LOW);
  }

  for (int LED = 2; LED <= 4; LED++){
  digitalWrite(LED, LOW);
  delay(50);
  }

  for (int LED = 4; LED >= 2; LED--){
    digitalWrite(LED, HIGH);
    delay(200);
    digitalWrite(LED, LOW);
  }

  for (int LED = 2; LED <=4; LED++){ 
    digitalWrite(LED, LOW);
    delay(50)
  }
}