void setup()
{
  pinMode(13, OUTPUT);
  pinMode(12, OUTPUT);
  pinMode(11, OUTPUT);
}

void loop()
 {
   digitalWrite(13, HIGH);
   digitalWrite(12, HIGH);
   digitalWrite(11, HIGH);

   delay(300);

   digitalWrite(13,LOW);
   digitalWrite(12, LOW);
   digitalWrite(11, LOW);

   delay(300);

}