void setup() {
  pinMode(16, OUTPUT);
  pinMode(17, OUTPUT);
  pinMode(27, OUTPUT);
  pinMode(25, OUTPUT);
  pinMode(26, OUTPUT);
  pinMode(18, OUTPUT);
}

void loop() {
  digitalWrite(16, HIGH);
  digitalWrite(25, HIGH);
  delay(1000); 
  digitalWrite(16, LOW);
  digitalWrite(25, LOW);
  delay(1000); 
  
  digitalWrite(17, HIGH);
  digitalWrite(26, HIGH);
  delay(1000);
  digitalWrite(17, LOW);
  digitalWrite(26, LOW);
  delay(1000);
  
  digitalWrite(27, HIGH);
  digitalWrite(18, HIGH);
  delay(1000);
  digitalWrite(27, LOW);
  digitalWrite(18, LOW);
  delay(1000);

 
}