int t = 550; 

void setup() {
  pinMode(2, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(18, OUTPUT);
  pinMode(19, OUTPUT);
}

void loop() {
  digitalWrite(2, HIGH);
  digitalWrite(4, HIGH);
  digitalWrite(5, HIGH);
  digitalWrite(18, HIGH);
  digitalWrite(19, HIGH);
  delay(t);
  digitalWrite(2, LOW);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(18, LOW);
  digitalWrite(19, LOW);
  delay(t);
}