void setup() {
  for(int i = 8; i<= 12; i++)
  {
    pinMode(i, OUTPUT);// put your setup code here, to run once:
  }
}

void loop() {
  for (int i = 8; i<= 12; i++)
  {
    digitalWrite(i, HIGH);
    delay(500);
    digitalWrite(i, HIGH);
    delay(500);
    digitalWrite(i, LOW);
    delay(50);
    digitalWrite(i, LOW);
    delay(500);// put your main code here, to run repeatedly:
  }
}