void setup() {

  pinMode(13, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(4, OUTPUT);

}

void loop() {

  digitalWrite(13, HIGH);
  delay(1000);  // delay time in milliseconds, the duration is 1 seconds    
  digitalWrite(13, LOW);
  delay(1000);

  digitalWrite(8, HIGH);
  delay(500);  // the duration is 0.5 seconds  
  digitalWrite(8, LOW);
  //digitalWrite(8, HIGH);
  //delay(500);
 // digitalWrite(8, LOW);
  delay(500);

  for (int i = 0; i < 3; i = i + 1) {

    digitalWrite(4, HIGH);
    delay(500);
    digitalWrite(4, LOW);
    delay(500);

  }

}