void setup(){
  // put your setup code here, to run once:
 pinMode(11,OUTPUT);
 pinMode(12,OUTPUT);
 pinMode(13,OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
   digitalWrite(11,HIGH);
   delay(1000);
   digitalWrite(11,LOW);
   delay(1000);
   digitalWrite(12, HIGH);
   delay(1000);
   digitalWrite(12,LOW);
   delay(1000);
   digitalWrite(13, HIGH);
   delay(1000);
   digitalWrite(13, LOW);
   delay(1000);
}